High-magnification large-target-surface telecentric lens and optical system thereof

Abstract

The utility model relates to the technical field of optical lenses, and discloses a high-magnification large-target-surface telecentric lens and an optical system thereof. The optical system is sequentially provided with a first lens G1 with positive focal power, a second lens G2 with positive focal power, a third lens G3 with negative focal power, a fourth lens G4 with positive focal power, a fifth lens G5 with positive focal power, a sixth lens G6 with negative focal power, a seventh lens G7 with positive focal power, a beam splitter prism BS and a diaphragm T from an object side to an image side. An eighth lens G8 with negative focal power; a ninth lens G9 with positive focal power; and a tenth lens G10 with positive focal power. The beam splitter prism BS is a semi-transparent and semi-reflective prism; and the diaphragm T is arranged at the focal point of the front group to form a telecentric framework. The optical system of the high-magnification large-target-surface telecentric lens provided by the utility model has higher magnification and larger numerical aperture, and can realize high-precision detection.

Description

Technical Field

[0001] This utility model relates to the field of optical lens technology, and in particular to a high-magnification, large-area telecentric lens and its optical system. Background Technology

[0002] In machine vision precision optical measurement systems, the use of ordinary industrial lenses can lead to problems such as different magnification due to changes in object distance, parallax, and large distortion. Telecentric lenses can reduce or even eliminate these problems. Within a certain object distance range, the magnification of the image can remain unchanged with changes in object distance. Its principle advantage makes it very suitable for precision measurement and inspection.

[0003] In high-precision inspection fields such as semiconductors, mini LEDs (Light Emitting Diodes), FPDs (Flat Panel Displays), and general semiconductors, there is a need for high-magnification telecentric lenses that support high-pixel, large-area cameras. Existing high-magnification telecentric lenses have target areas that are almost all below 1.1 inches, which does not meet the inspection requirements. On the other hand, the coaxial illumination of existing high-magnification telecentric lenses simply places a general point light source at the aperture. Due to the small light-emitting area of ​​the point light source and the generally large numerical aperture of high-magnification telecentric lenses, the point light source and the entrance pupil of the telecentric lens are mismatched, which cannot form good coaxial incident illumination. This not only reduces the imaging contrast but also creates hotspot effects and stray light.

[0004] The above information is provided as background information only to aid in understanding this disclosure and does not constitute an assertion or admission that any of the above content can be used as prior art relative to this disclosure. Utility Model Content

[0005] The purpose of this invention is to provide a high-magnification, large-area telecentric lens and its optical system to solve or at least partially solve the technical problems existing in the prior art.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, this utility model provides an optical system for a high-magnification, large-target-area telecentric lens, comprising, in order from the object side to the image side, a first lens G1 with positive optical power, a second lens G2 with positive optical power, a third lens G3 with negative optical power, a fourth lens G4 with positive optical power, a fifth lens G5 with positive optical power, a sixth lens G6 with negative optical power, a seventh lens G7 with positive optical power, a beam splitter BS, an aperture T, an eighth lens G8 with negative optical power, a ninth lens G9 with positive optical power, and a tenth lens G10 with positive optical power.

[0008] The first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6 and the seventh lens G7 form the front group (100); the beam splitter BS is a semi-transparent and semi-reflective prism; the aperture T is set at the focal point of the front group (100) to form a telecentric structure.

[0009] The working distance of the optical system is WD, and the numerical aperture of the optical system is NA. WD and NA satisfy the relationship: NA×WD<15.

[0010] Optionally, the focal length of the front group is f 100 f 100 The relationship between WD and f is: 0.48 < |f 100 / WD|<0.88;

[0011] The ninth lens G9 and the tenth lens G10 form the rear group, and the focal length of the rear group is f. 200 The focal length of the eighth lens G8 is f8, and f8 is the same as f... 200 The relation is satisfied: 0.2 < |f8 / f 200 |<0.5.

[0012] Optionally, the second lens G2, the third lens G3 and the fourth lens G4 form a cemented triplet lens group U1, and the fifth lens G5 and the sixth lens G6 form a cemented doublet lens group U2.

[0013] The focal length of the first lens G1 is f1, and f1 and f 100 Satisfies the relation: 1.3 < |f1 / f 100 |<2.3;

[0014] The focal length of the triple-cemented lens group U1 is f U1 f U1 with f 100 Satisfy the relation: |f 100 / f U1 |<0.15;

[0015] The focal length of the seventh lens G7 is f7, and f7 is the same as f... 100 The relation 1.3 < |f7 / f is satisfied. 100 |<2;

[0016] The focal length of the cemented doublet U2 is f. U2 f U2 with f 100 Satisfy the relation: |f 100 / f U2 |<0.25.

[0017] Optionally, the first lens G1, the second lens G2, the fourth lens G4, the fifth lens G5, and the seventh lens G7 are all biconvex lenses; the third lens G3 and the eighth lens G8 are both biconcave lenses; and the sixth lens G6, the ninth lens G9, and the tenth lens G10 are all meniscus lenses.

[0018] Optionally, in the cemented triplet lens group U1, the refractive index Nd2 of the second lens G2 and the Abbe number Vd2 of the second lens G2 satisfy the following relationship: 1.42 <Nd2<1.65,60<Vd2<95;

[0019] The refractive index Nd4 of the fourth lens G4 and its Abbe number Vd4 satisfy the following relationship: Fourth lens: 1.42 <Nd4<1.65,60<Vd4<95。

[0020] Optionally, the optical system further includes a coaxial illumination assembly;

[0021] The coaxial illumination assembly is arranged on the reflected light path of the beam splitter BS, and includes a second condenser lens C2, a first condenser lens C1 and a reflector M arranged sequentially from the light-inlet surface A to the light-outlet surface B of the point light source.

[0022] The first condenser lens C1 and the second condenser lens C2 are used to magnify and shape the incident beam from the point light source so that the angle and spot size of the beam at the light-emitting surface B match the aperture of the aperture T; the reflector M is used to deflect the shaped beam.

[0023] Optionally, the first condenser lens C1 and the second condenser lens C2 form a condenser lens group, which has positive optical power and a combined focal length of f. 310 f 310 Satisfying the relation: 8 <f 310 <18.

[0024] Optionally, the optical axes of the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, and the tenth lens G10 all coincide with a predetermined optical axis.

[0025] The optical axis of the first condenser lens C1 coincides with the optical axis of the second condenser lens C2, and the optical axis of the first condenser lens C1 is parallel to the predetermined optical axis.

[0026] Optionally, the aperture of the stop T is a circular hole, and the center of the circular hole is on the predetermined optical axis.

[0027] Secondly, this utility model provides a high-magnification, large-area telecentric lens, including the optical system of a high-magnification, large-area telecentric lens as described above.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The optical system of the high-magnification, large-area telecentric lens provided by this utility model has a high magnification and a large numerical aperture, which can achieve high-precision detection. The maximum imaging area reaches Φ44mm, and it can be used with cameras such as 6500W pixel, 38mm diagonal area array camera or 8k 5μm line scan camera to meet the needs of high-precision detection fields such as semiconductors, mini LEDs, FPDs and general semiconductors.

[0030] This invention has other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and the following detailed description, which together serve to explain the particular principles of this invention. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the optical system of a high-magnification, large-target-area telecentric lens provided in an embodiment of this utility model.

[0033] Figure 2 yes Figure 1 A schematic diagram of the optical path.

[0034] Figure 3 This is a schematic diagram of the coaxial illumination component of an optical system for a high-magnification, large-target-area telecentric lens provided in this embodiment of the present invention.

[0035] Figure 4 This is the MTF diagram of an optical system for a high-magnification, large-target-area telecentric lens provided in this embodiment of the present invention.

[0036] Figure 5 This is an optical distortion curve diagram of an optical system for a high-magnification, large-area telecentric lens provided in this embodiment of the present invention. Detailed Implementation

[0037] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0038] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0039] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0040] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0041] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0042] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0043] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0044] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do 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, they should not be construed as limitations on the embodiments of this application.

[0045] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "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 a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0046] Example 1:

[0047] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the optical system of a high-magnification, large-target-area telecentric lens provided in an embodiment of the present invention. Figure 2 yes Figure 1 Schematic diagram of the optical path;

[0048] like Figure 1 As shown, the optical system includes:

[0049] The following lenses are arranged sequentially from the object side to the image side: a first lens G1 with positive optical power, a second lens G2 with positive optical power, a third lens G3 with negative optical power, a fourth lens G4 with positive optical power, a fifth lens G5 with positive optical power, a sixth lens G6 with negative optical power, a seventh lens G7 with positive optical power, a beam splitter BS, an aperture T, an eighth lens G8 with negative optical power, a ninth lens G9 with positive optical power, and a tenth lens G10 with positive optical power.

[0050] The first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, and the seventh lens G7 form the front group 100; the beam splitter prism BS is a semi-transparent and semi-reflective prism; the aperture T is located at the focal point of the front group 100, forming a telecentric structure.

[0051] The working distance of the optical system is WD, and the numerical aperture of the optical system is NA. WD and NA satisfy the relationship: NA×WD<15.

[0052] Furthermore, the focal length of the front element 100 is f. 100 f 100 The relationship between WD and f is: 0.48 < |f 100 / WD|<0.88;

[0053] The ninth lens G9 and the tenth lens G10 form the rear group 200, and the focal length of the rear group 200 is f. 200 The focal length of the eighth lens G8 is f8, and f8 is the same as f... 200 The relation is satisfied: 0.2 < |f8 / f 200 |<0.5.

[0054] Specifically, the second lens G2, the third lens G3 and the fourth lens G4 form a cemented triplet lens group U1, and the fifth lens G5 and the sixth lens G6 form a cemented doublet lens group U2.

[0055] The focal length of the first lens G1 is f1, and f1 and f 100 Satisfies the relation: 1.3 < |f1 / f 100 |<2.3; The focal length of the triplex lens group U1 is f U1 f U1 with f 100 Satisfy the relation: |f 100 / f U1 |<0.15;

[0056] The focal length of the seventh lens G7 is f7, and f7 is the same as f... 100 The relation 1.3 < |f7 / f is satisfied. 100 |<2;

[0057] The focal length of the cemented doublet U2 is f. U2 f U2 with f 100 Satisfy the relation: |f 100 / f U2 |<0.25.

[0058] like Figure 2 As shown, the first lens G1 has a large light-refraction capability, forming light rays that are nearly parallel to the optical axis and enter the subsequent lens. In this embodiment, the first lens G1 is made of a material with a high refractive index, which is beneficial to reducing spherical aberration.

[0059] The triplet lens group U1 and the doublet lens group U2 have small optical power. Light rays pass through U1 and U2 in near parallel. Their cemented surfaces have negative optical power, which can correct spherical aberration and higher-order aberrations of the optical system.

[0060] More specifically, the first lens G1, the second lens G2, the fourth lens G4, the fifth lens G5, and the seventh lens G7 are all biconvex lenses; the third lens G3 and the eighth lens G8 are both biconcave lenses; and the sixth lens G6, the ninth lens G9, and the tenth lens G10 are all meniscus lenses.

[0061] Both the front group 100 and the rear group 200 have positive optical power. Combined with the seventh lens G7, which has negative optical power, they can effectively correct the system's ground curvature and spherical aberration. The ninth lens G9 is a meniscus structure that bends toward the aperture stop T, and the tenth lens G10 is a meniscus structure that bends toward the image plane. This combination of structures can correct the system's coma, astigmatism, and distortion.

[0062] Furthermore, in the cemented triplet lens group U1, the refractive index Nd2 of the second lens G2 and the Abbe number Vd2 of the second lens G2 satisfy the following relationship: 1.42 <Nd2<1.65,60<Vd2<95;

[0063] The refractive index Nd4 of the fourth lens G4 and its Abbe number Vd4 satisfy the following relationship: Fourth lens: 1.42 <Nd4<1.65,60<Vd4<95。

[0064] Using a lens combination that satisfies the above refractive index and dispersion relationship is more conducive to correcting system chromatic aberration.

[0065] Please combine Figure 2 and Figure 3 , Figure 3 for Figure 3 This is a schematic diagram of the coaxial illumination assembly of an optical system for a high-magnification, large-target-area telecentric lens provided in this embodiment of the present invention.

[0066] The optical system also includes a coaxial illumination assembly 300;

[0067] The coaxial illumination assembly 300 is positioned on the reflected light path of the beam splitter BS, such as... Figure 3 As shown, the coaxial lighting assembly 300 includes a second condenser lens C2, a first condenser lens C1, and a reflector M arranged sequentially from the light-inlet surface A to the light-outlet surface B of the point light source;

[0068] The first condenser lens C1 and the second condenser lens C2 are used to magnify and shape the incident beam from the point light source, so that the angle and spot size of the beam at the light-emitting surface B match the aperture of the aperture T, thereby forming good coaxial incident illumination, reducing hotspot effect and stray light, and improving imaging contrast; the reflector M is used to deflect the shaped beam, which can reduce the structural size.

[0069] In this embodiment, the specifications of the first condenser lens C1 and the second condenser lens C2 are set to be the same, which can reduce production costs.

[0070] Specifically, the first condenser lens C1 and the second condenser lens C2 form a condenser lens group 310, which has positive optical power and a combined focal length of f. 310 f 310 Satisfying the relation: 8 <f 310 <18.

[0071] In this embodiment, the optical axes of the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, and the tenth lens G10 all coincide with a predetermined optical axis.

[0072] The optical axis of the first condenser lens C1 coincides with the optical axis of the second condenser lens C2, and the optical axis of the first condenser lens C1 is parallel to the predetermined optical axis.

[0073] In this embodiment, the aperture of the stop T is a circular hole, and the center of the circular hole is on the predetermined optical axis. It is understood that the aperture value of the stop T needs to be adjusted according to the specific application scenario.

[0074] Furthermore, to evaluate whether the performance of this optical system meets the expected requirements, specific application examples and experimental verifications are provided below;

[0075] In this application example, the relevant data for the optical system are shown in Table 1:

[0076] Table 1

[0077]

[0078]

[0079] 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".

[0080] In this application example, the combined focal length f of the first 100 elements is... 100 =57mm; the focal length of the first lens G1 is f1=102mm; the focal length of the three-cement lens group U1 is f U1 = -577mm; the focal length of the cemented doublet U2 is f U2 =324mm; the focal length of the seventh lens G7 is f7=94mm; the focal length of the eighth lens G8 is f8=-25mm; the focal length of the ninth lens G9 is f9=134mm; the focal length of the tenth lens G10 is f 10 =160mm; the focal length of the 200-group lens assembly is f 200 =72mm; the combined focal length of the condenser lens group 310 is f 310 =14.5mm.

[0081] In this application example, the optical path data for the coaxial lighting component 300 is shown in Table 2 below:

[0082] Table 2

[0083] surface Radius (mm) Thickness (mm) Refractive index Incident surface A ∞ 14 C1 front surface 57.50 3.0 1.50 C1 rear surface -16.20 3.8 C2 front surface 57.50 3.0 1.50 C2 rear surface -16.20 20 Mirror M ∞ 26 Light-emitting surface B ∞

[0084] The optical parameters of the optical system are shown in Table 3 below:

[0085] Table 3

[0086]

[0087]

[0088] Substituting the above values ​​into the respective relations, we obtain:

[0089] NA×WD|=13.28,|f 100 / WD|=0.687,|f8 / f 200 |=0.347,|f1 / f 100 |=1.789,

[0090] |f 100 / f U1 |=0.099,|f7 / f 100 |=1.649,|f8 / f200 |=0.347,|f 100 / f U2 |=0.176.

[0091] Therefore, the relevant relational expression in this embodiment is satisfied, namely:

[0092] NA×WD<15, 0.48<|f 100 / WD|<0.88, 0.2<|f8 / f 200 |<0.5, 1.3<|f1 / f 100 |<2.3,

[0093] |f 100 / f U1 |<0.15, 1.3<|f7 / f 100 |<2,0.2<|f8 / f 200 |<0.5,|f 100 / f U2 |<0.25.

[0094] Please continue to refer to this. Figure 4 and Figure 5 , Figure 4 This is an MTF diagram of the optical system of a high-magnification, large-area telecentric lens provided in this embodiment of the invention. Figure 5 This is an optical distortion curve diagram of an optical system for a high-magnification, large-target-area telecentric lens provided in this embodiment of the present invention.

[0095] Experimental verification shows that the distortion of the optical system is less than 0.1%.

[0096] In summary, this embodiment realizes an optical system for a high-magnification, large-target-area telecentric lens, which has a high magnification and a large numerical aperture, with a maximum imaging area of ​​Φ44mm, enabling high-precision detection. Furthermore, by combining a coaxial illumination scheme, this optical system effectively improves the problem of poor coaxial illumination effect of existing high-magnification telecentric lenses.

[0097] Example 2:

[0098] This embodiment provides a high-magnification, large-area telecentric lens, including the optical system of a high-magnification, large-area telecentric lens as described in Embodiment 1.

[0099] Since the optical system has been described in detail in Embodiment 1, it will not be repeated in this embodiment.

[0100] This embodiment provides a high-magnification telecentric lens with a large target area, achieving an imaging target area of ​​Φ44mm. It can be used with cameras such as 6500W pixels, 38mm diagonal area array cameras, or 8k 5μm line scan cameras. Furthermore, the coaxial illumination scheme in its optical system can effectively improve the problem of poor illumination effect of existing high-magnification telecentric lenses.

[0101] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model 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 this utility model.

Claims

1. An optical system of a high-magnification large-target far- focus lens, characterized by comprising: The optical system comprises, arranged in order from the object side to the image side, a first lens G1 having positive refractive power, a second lens G2 having positive refractive power, a third lens G3 having negative refractive power, a fourth lens G4 having positive refractive power, a fifth lens G5 having positive refractive power, a sixth lens G6 having negative refractive power, a seventh lens G7 having positive refractive power, a beam splitter BS, a diaphragm T, an eighth lens G8 having negative refractive power, a ninth lens G9 having positive refractive power, and a tenth lens G10 having positive refractive power; The first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, and the seventh lens G7 form a front group (100); the beam splitter BS is a semi-transmissive and semi-reflective prism; and the diaphragm T is arranged at a focal point of the front group (100) to form a telecentric architecture. The working distance of the optical system is WD, and the numerical aperture of the optical system is NA, and the WD and the NA satisfy a relationship: NA*WD<15.

2. The optical system of claim 1, wherein, The focal length of the front group (100) is f 100 , f 100 and the WD satisfies the relationship: 0.48 < |f 100 / WD| < 0.

88. The ninth lens G9 and the tenth lens G10 form a rear group (200), and the focal length of the rear group (200) is f 200 ; the focal length of the eighth lens G8 is f8, and f8 and f 200 satisfy the relationship: 0.2 < |f8 / f 200 | < 0.

5.

3. The optical system of claim 2, wherein, The second lens G2, the third lens G3, and the fourth lens G4 form a three-lens cemented lens group U1, and the fifth lens G5 and the sixth lens G6 form a two-lens cemented lens group U2. The focal length of the first lens G1 is f1, and f1 and f 100 satisfies the relationship: 1.3 < |f1 / f 100 | < 2.3; The focal length of the triplet lens group U1 is f U1 , f U1 , and f 100 satisfy the relationship: |f 100 / f U1 | < 0.

15. The focal length of the seventh lens G7 is f7, and f7 and f 100 satisfy the relationship: 1.3 < |f7 / f 100 | < 2; The focal length of the doublet lens group U2 is f U2 , f U2 and f 100 satisfy the relationship: |f 100 / f U2 | < 0.

25.

4. The optical system of claim 3, wherein, The first lens G1, the second lens G2, the fourth lens G4, the fifth lens G5, and the seventh lens G7 are all double-convex lenses; the third lens G3 and the eighth lens G8 are both double-concave lenses; and the sixth lens G6, the ninth lens G9, and the tenth lens G10 are all meniscus lenses.

5. The optical system of claim 3, wherein, In the three-lens cemented lens group U1, the refractive index Nd2 of the second lens G2 and the Abbe number Vd2 of the second lens G2 satisfy a relationship: 1.42<Nd2<1.65, and 60<Vd2<95. The refractive index Nd4 of the fourth lens G4 and the Abbe number Vd4 of the fourth lens G4 satisfy a relationship: 1.42<Nd4<1.65, and 60<Vd4<95.

6. The optical system of claim 3, wherein, The optical system further comprises a coaxial illumination assembly (300); The coaxial illumination assembly (300) is arranged on a reflected light path of the beam splitter BS and comprises, arranged in order from an incident light surface A of a point light source to an outgoing light surface B, a second condenser lens C2, a first condenser lens C1, and a mirror M. The first condenser lens C1 and the second condenser lens C2 are used to magnify and shape the incident light beam of the point light source, so that the angle and the spot size of the light beam at the outgoing light surface B are matched with the aperture of the diaphragm T; and the mirror M is used to fold the shaped light beam.

7. The optical system of claim 6, wherein, The first condenser lens C1 and the second condenser lens C2 constitute a condenser lens group (310) having a positive refractive power with a combined focal length of f 310 , f 310 satisfying the relationship: 8 < f 310 <18.

8. The optical system of claim 7, wherein, The optical axes of the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, and the tenth lens G10 all coincide with a predetermined optical axis. The optical axis of the first condenser lens C1 coincides with the optical axis of the second condenser lens C2, and the optical axis of the first condenser lens C1 is parallel to the predetermined optical axis.

9. The optical system of claim 8, wherein, The aperture of the diaphragm T is a circular hole, and the center of the circular hole is on the predetermined optical axis.

10. A high-magnification large target far- focus lens, characterized in that, The optical system comprises a high-magnification large-target far-field lens according to any one of claims 1-9.

Images