Large-view full-frame telecentric lens and optical system thereof
By designing the optical system of a large-field-of-view full-frame telecentric lens, and adopting a double telecentric structure composed of glass spherical lenses, the focal length and outer diameter of the lenses were optimized. This solved the problems of limited field of view and large distortion in existing telecentric lenses, achieving high resolution and low distortion, and meeting high inspection requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-22
- Publication Date
- 2026-03-31
AI Technical Summary
Existing large-field telecentric lenses cannot meet market demand, especially in the new energy and electric vehicle manufacturing fields with high inspection requirements, and they also suffer from problems such as limited field of view and large distortion.
Design an optical system for a large-field-of-view full-frame telecentric lens. The system employs a double telecentric structure composed of glass spherical lenses, including a lens combination with positive optical power. By optimizing the relationship between the lens focal length and outer diameter, the outer diameter of the lens is reduced, thereby achieving high resolution and low distortion.
It achieves a field of view of Φ300mm, MTF value >0.3, distortion less than 0.02%, supports full-frame cameras, and reduces production costs and system weight.
Smart Images
Figure CN224067068U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of machine vision lens technology, and in particular to a large field of view full-frame telecentric lens and its optical system. Background Technology
[0002] In machine vision precision optical measurement systems, the use of ordinary industrial lenses presents problems such as varying magnification due to changes in object distance, parallax, and large distortion, making it difficult to meet high detection requirements. Telecentric lenses, on the other hand, can reduce or even eliminate these problems. Within a certain object distance range, the magnification of the obtained image does not change with the object distance, making it very suitable for precision measurement and inspection fields.
[0003] With the rapid development of industries such as new energy and electric vehicle manufacturing, the application scenarios of large-field telecentric lenses are increasing. Currently, most telecentric lenses on the market have a field of view of less than Φ150mm, which cannot meet the market demand. Therefore, there is an urgent need in this field for telecentric lenses with a larger field of view, and at the same time, features such as high telecentricity and low distortion, so as to meet the high inspection requirements of today's market.
[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 large-field-of-view full-frame 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 large-field-of-view full-frame 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 positive optical power, a fourth lens G4 with negative optical power, an aperture stop S, a fifth lens G5 with negative optical power, a sixth lens G6 with positive optical power, a seventh lens G7 with positive optical power, and an eighth lens G8 with positive optical 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, the seventh lens G7, and the eighth lens G8 are all glass spherical lenses, which together form a double telecentric structure, wherein the first lens G1 has the largest outer diameter;
[0008] The third lens G3 and the fourth lens G4 form a cemented lens U1, and the fifth lens G5 and the sixth lens G6 form a cemented lens U2.
[0009] Optionally, the center distance between the first lens G1 and the second lens G2 is L1, the focal length of the first lens G1 is f1, the focal length of the second lens G2 is f2, and the focal length of the cemented lens group U1 is f1. U1 ;
[0010] f1 and L1 satisfy the following relationship: 0.9 < |f1 / L1| < 1.5;
[0011] f U1 f2 and f2 satisfy the relationship: 0.4 < |f U1 / f2|<0.8.
[0012] Optionally, the center distance between the aperture stop S and the image plane is L2, and the focal length of the cemented lens group U2 is f. U2 The focal length of the seventh lens G7 is f7, and the focal length of the eighth lens G8 is f8.
[0013] f U2 The relationship between L2 and f is: 0.24 < |f U2 / L2|<0.65;
[0014] f7 and L2 satisfy the relationship: 0.25 < |f7 / L2| < 0.6;
[0015] f8 and L2 satisfy the following relationship: 0.5 < |f8 / L2| < 0.9.
[0016] Optionally, the half-image height of the optical system is y', and the half-field of view is h;
[0017] The relationship between y' and h is: |y' / h|<0.5.
[0018] Optionally, the first lens G1 is a plano-convex lens, the second lens G2 is a meniscus lens, the third lens G3 is a meniscus lens, the fourth lens G4 is a meniscus lens; the fifth lens G5 is a biconcave lens, the sixth lens G6 is a biconvex lens, the seventh lens G7 is a meniscus lens, and the eighth lens G8 is a biconvex lens.
[0019] Optionally, the ratio of the outer diameter of the first lens G1 to the outer diameter of the second lens G2 is greater than 3.85.
[0020] Optionally, the outer diameter of both the cemented lens U1 and the cemented lens U2 is smaller than the outer diameter of the second lens G2.
[0021] 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, and the eighth lens G8 are all on a predetermined optical axis.
[0022] Optionally, the aperture of the stop S is a circular hole, and the center of the circular hole is on the predetermined optical axis.
[0023] Secondly, this utility model provides a large field of view full-frame telecentric lens, including the optical system of a large field of view full-frame telecentric lens as described above.
[0024] Compared with the prior art, the present invention has the following beneficial effects:
[0025] The optical system with a dual telecentric structure provided by this invention has a resolution of 145 lp / mm, a field of view of up to Φ300mm, an MTF value of >0.3 across the entire field of view, and a distortion of less than 0.02%. It supports full-frame cameras and significantly reduces the outer diameter of the lens after the first lens, effectively reducing manufacturing costs.
[0026] 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
[0027] 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.
[0028] Figure 1 This is a schematic diagram of the optical system of a large-field-of-view full-frame telecentric lens provided in an embodiment of this utility model.
[0029] Figure 2 An optical path diagram of an optical system for a large-field-of-view full-frame telecentric lens provided for an embodiment of this utility model.
[0030] Figure 3 The MTF curve of the optical system of a large field-of-view full-frame telecentric lens provided in Embodiment 1 of this utility model.
[0031] Figure 4 The distortion diagram is shown for the optical system of a large field-of-view full-frame telecentric lens provided in Embodiment 1 of this utility model.
[0032] Figure 5 MTF curve of an optical system for a large field-of-view full-frame telecentric lens provided in Embodiment 2 of this utility model.
[0033] Figure 6The distortion diagram is shown for the optical system of a large field-of-view full-frame telecentric lens provided in Embodiment 2 of this utility model. Detailed Implementation
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] As understood 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.
[0041] 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.
[0042] 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.
[0043] Example 1:
[0044] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the optical system of a large-field-of-view full-frame telecentric lens provided in an embodiment of this utility model. Figure 2 An optical path diagram of an optical system for a large-field-of-view full-frame telecentric lens provided for an embodiment of this utility model.
[0045] like Figure 1 As shown, the optical system includes:
[0046] 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 positive optical power, a fourth lens G4 with negative optical power, an aperture S, a fifth lens G5 with negative optical power, a sixth lens G6 with positive optical power, a seventh lens G7 with positive optical power, and an eighth lens G8 with positive optical power.
[0047] In this embodiment, 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, and the eighth lens G8 are all glass spherical lenses. These lenses together form a structure as shown in the figure. Figure 1 The double-distal-centered structure shown;
[0048] Among them, the outer diameter of the first lens G1 is much larger than the outer diameter of all subsequent lenses; specifically, the ratio of the outer diameter of the first lens G1 to the outer diameter of the second lens G2 is greater than 3.85, and the outer diameter of the second lens G2 is larger than the outer diameter of the other lenses; for example... Figure 1 As shown, the outer diameters of both cemented lens U1 and cemented lens U2 are smaller than the outer diameter of the second lens G2.
[0049] Furthermore, the third lens G3 and the fourth lens G4 form a cemented lens U1, and the fifth lens G5 and the sixth lens G6 form a cemented lens U2.
[0050] The first lens G1, the second lens G2 and the cemented lens U1 form the front group of the optical system, and the cemented lens U2, the seventh lens G7 and the eighth lens G8 form the rear group of the optical system.
[0051] like Figure 1 As shown, the center distance between the first lens G1 and the second lens G2 is L1, and the center distance between the aperture stop S and the image plane is L2.
[0052] Specifically, the focal length of the first lens G1 is f1, the focal length of the second lens G2 is f2, and the focal length of the cemented lens group U1 is f. U1 ;
[0053] f1 and L1 satisfy the relationship: 0.9 < |f1 / L1| < 1.5; by satisfying the above relationship, the outer diameter of the second lens G2 and the cemented lens group U1 can be significantly reduced, effectively reducing the manufacturing cost and system weight;
[0054] f U1 f2 and f2 satisfy the relationship: 0.4 < |f U1 / f2|<0.8.
[0055] Specifically, the focal length of the cemented lens group U2 is f. U2The focal length of the seventh lens G7 is f7, and the focal length of the eighth lens G8 is f8.
[0056] f U2 The relationship between L2 and f is: 0.24 < |f U2 / L2|<0.65;
[0057] f7 and L2 satisfy the relationship: 0.25 < |f7 / L2| < 0.6;
[0058] f8 and L2 satisfy the following relationship: 0.5 < |f8 / L2| < 0.9.
[0059] Furthermore, the half-image height of the optical system is y', and the half-field of view is h; y' and h satisfy the relationship: |y' / h|<0.5.
[0060] More specifically, in this embodiment, the first lens G1 is a plano-convex lens, the second lens G2 is a meniscus lens, the third lens G3 is a meniscus lens, the fourth lens G4 is a meniscus lens; the fifth lens G5 is a biconcave lens, the sixth lens G6 is a biconvex lens, the seventh lens G7 is a meniscus lens, and the eighth lens G8 is a biconvex lens.
[0061] 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, and the eighth lens G8 are all on a predetermined optical axis.
[0062] The aperture of stop S is a circular hole, and the center of the circular hole is on the predetermined optical axis.
[0063] Understandably, the aperture value of stop S needs to be adjusted according to the specific application scenario.
[0064] To verify whether the optical system described above meets the design objectives, the following is a specific test example based on the above settings in this embodiment:
[0065] In this test example, the lens data of the optical system are shown in Table 1 below:
[0066] Table 1
[0067]
[0068] 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 left 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 1On 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".
[0069] In this test example, the telecentric lens optical system has a distance of L1 = 599.7 mm, a distance of L2 = 210 mm, a focal length of f1 = 785 mm for the first lens G1, a focal length of f2 = 287 mm for the second lens G2, and a focal length of f1 for the cemented lens group U1. U1 =-175mm, focal length f of cemented lens group U2 U2 =-91mm, the focal length of the seventh lens G7 is f7=94mm, and the focal length of the eighth lens G8 is f8=147mm.
[0070] Substituting the above values into the respective relations, we obtain:
[0071] |f1 / L1|=1.309, |f U1 / f2|=0.610,|f U2 / L2|=0.433, |f7 / L2|=0.448, |f8 / L2|=0.7.
[0072] Therefore, the relevant relational expression in this embodiment is satisfied, namely:
[0073] 0.9 < |f1 / L1| < 1.5, 0.4 < |f U1 / f2|<0.8, 0.24<|f U2 / L2|<0.65, 0.25<|f7 / L2|<0.6, 0.5<|f8 / L2|<0.9.
[0074] As can be seen from Table 1, the outer diameter of the second lens G2 and the cemented lens group U1 is much smaller than that of the first lens G1, which can effectively reduce manufacturing costs and system weight.
[0075] The optical system features a dual telecentric structure, a working distance of 500mm, an object-side field of view of Φ300mm, and a half-image height of y'=22mm, supporting full-frame high-resolution cameras.
[0076] Please refer to Figure 3 and Figure 4 , Figure 3 The MTF (Modulation Transfer Function) curve of the optical system of a large-field-of-view full-frame telecentric lens provided in Embodiment 1 of this utility model is shown. Figure 4 The distortion diagram of the optical system of a large field-of-view full-frame telecentric lens provided in Embodiment 1 of this utility model;
[0077] like Figure 3 and Figure 4As shown, the optical system in this test example has an MTF value >0.3 and distortion less than 0.01% at 145 lp / mm across the entire field of view.
[0078] In summary, the optical system of the large field-of-view full-frame telecentric lens provided in this embodiment achieves a telecentric optical system with a field of view of Φ300mm through reasonable lens combination design and focal length matching, with a full field-of-view distortion of less than 0.02% and a resolution of 145lp / mm, supporting full-frame cameras; this optical system can significantly reduce the outer diameter of the lenses after the first lens G1, effectively reducing manufacturing costs.
[0079] Example 2:
[0080] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the optical system of a large-field-of-view full-frame telecentric lens provided in an embodiment of this utility model. Figure 2 An optical path diagram of an optical system for a large-field-of-view full-frame telecentric lens provided for an embodiment of this utility model.
[0081] like Figure 1 As shown, the optical system includes:
[0082] 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 positive optical power, a fourth lens G4 with negative optical power, an aperture S, a fifth lens G5 with negative optical power, a sixth lens G6 with positive optical power, a seventh lens G7 with positive optical power, and an eighth lens G8 with positive optical power.
[0083] In this embodiment, 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, and the eighth lens G8 are all glass spherical lenses. These lenses together form a structure as shown in the figure. Figure 1 The double-distal-centered structure shown;
[0084] Among them, the outer diameter of the first lens G1 is much larger than the outer diameter of all subsequent lenses; specifically, the ratio of the outer diameter of the first lens G1 to the outer diameter of the second lens G2 is greater than 3.85, and the outer diameter of the second lens G2 is larger than the outer diameter of the other lenses; for example... Figure 1 As shown, the outer diameters of both cemented lens U1 and cemented lens U2 are smaller than the outer diameter of the second lens G2.
[0085] Furthermore, the third lens G3 and the fourth lens G4 form a cemented lens U1, and the fifth lens G5 and the sixth lens G6 form a cemented lens U2.
[0086] The first lens G1, the second lens G2 and the cemented lens U1 form the front group of the optical system, and the cemented lens U2, the seventh lens G7 and the eighth lens G8 form the rear group of the optical system.
[0087] like Figure 1 As shown, the center distance between the first lens G1 and the second lens G2 is L1, and the center distance between the aperture stop S and the image plane is L2.
[0088] Specifically, the focal length of the first lens G1 is f1, the focal length of the second lens G2 is f2, and the focal length of the cemented lens group U1 is f. U1 ;
[0089] f1 and L1 satisfy the relationship: 0.9 < |f1 / L1| < 1.5; by satisfying the above relationship, the outer diameter of the second lens G2 and the cemented lens group U1 can be significantly reduced, effectively reducing the manufacturing cost and system weight;
[0090] f U1 f2 and f2 satisfy the relationship: 0.4 < |f U1 / f2|<0.8.
[0091] Specifically, the focal length of the cemented lens group U2 is f. U2 The focal length of the seventh lens G7 is f7, and the focal length of the eighth lens G8 is f8.
[0092] f U2 The relationship between L2 and f is: 0.24 < |f U2 / L2|<0.65;
[0093] f7 and L2 satisfy the relationship: 0.25 < |f7 / L2| < 0.6;
[0094] f8 and L2 satisfy the following relationship: 0.5 < |f8 / L2| < 0.9.
[0095] Furthermore, the half-image height of the optical system is y', and the half-field of view is h; y' and h satisfy the relationship: |y' / h|<0.5.
[0096] More specifically, in this embodiment, the first lens G1 is a plano-convex lens, the second lens G2 is a meniscus lens, the third lens G3 is a meniscus lens, the fourth lens G4 is a meniscus lens; the fifth lens G5 is a biconcave lens, the sixth lens G6 is a biconvex lens, the seventh lens G7 is a meniscus lens, and the eighth lens G8 is a biconvex lens.
[0097] 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, and the eighth lens G8 are all on a predetermined optical axis.
[0098] The aperture of stop S is a circular hole, and the center of the circular hole is on the predetermined optical axis.
[0099] Understandably, the aperture value of stop S needs to be adjusted according to the specific application scenario.
[0100] To verify whether the optical system described above meets the design objectives, the following is a specific test example based on the above settings in this embodiment:
[0101] In this test example, the lens data of the optical system are shown in Table 2 below:
[0102] Table 2
[0103]
[0104] It should be noted that in Table 2, "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 left surface. Figure 1 The right side surface of the corresponding lens or lens group; or it can be understood as: the object surface in Figure 1 On the left, the image plane (or image surface) is... Figure 1 On the right side, the surface closer to the object is called the "front surface", and the surface closer to the image is called the "back surface".
[0105] In this test example, the telecentric lens optical system has a distance of L1 = 716.7 mm, a distance of L2 = 215 mm, a focal length of f1 = 938 mm for the first lens G1, a focal length of f2 = 290 mm for the second lens G2, and a focal length of f1 for the cemented lens group U1. U1 = -165mm, focal length f of cemented lens group U2 U2 = -97mm, the focal length of the seventh lens G7 is f7=99mm, and the focal length of the eighth lens G8 is f8=153mm.
[0106] Substituting the above values into the respective relations, we obtain:
[0107] |f1 / L1|=1.309, |f U1 / f2|=0.569,|f U2 / L2|=0.451, |f7 / L2|=0.460, |f8 / L2|=0.712.
[0108] Therefore, the relevant relational expression in this embodiment is satisfied, namely:
[0109] 0.9 < |f1 / L1| < 1.5, 0.4 < |f U1 / f2|<0.8, 0.24<|f U2 / L2|<0.65, 0.25<|f7 / L2|<0.6, 0.5<|f8 / L2|<0.9.
[0110] As can be seen from Table 2, the outer diameter of the second lens G2 and the cemented lens group U1 is much smaller than that of the first lens G1, which can effectively reduce manufacturing costs and system weight.
[0111] In this test example, the optical system is a dual telecentric structure with a working distance of 550mm, an object-side field of view of Φ350mm, a half-image height of y'=22mm, and supports full-frame high-resolution cameras.
[0112] Please refer to Figure 5 and Figure 6 , Figure 5 The MTF curve of the optical system of a large-field-of-view full-frame telecentric lens provided in Embodiment 2 of this utility model. Figure 6 Distortion diagram of the optical system of a large field-of-view full-frame telecentric lens provided in Embodiment 2 of this utility model;
[0113] like Figure 5 and Figure 6 As shown, the optical system in this test example has an MTF value >0.3 and distortion less than 0.02% at 145 lp / mm across the entire field of view.
[0114] In summary, the optical system of the large-field-of-view full-frame telecentric lens provided in this embodiment, through reasonable lens combination design and focal length matching, achieves a telecentric optical system with a field of view of Φ300mm, a full-field-of-view distortion of less than 0.02%, a resolution of 145lp / mm, and supports full-frame cameras. This optical system can significantly reduce the outer diameter of the lenses after the first lens G1, effectively reducing manufacturing costs.
[0115] Example 3:
[0116] This embodiment provides a large field-of-view full-frame telecentric lens, including the optical system of a large field-of-view full-frame telecentric lens as described in Embodiment 1 or Embodiment 2.
[0117] Since the optical system has been described in detail in the above embodiments, it will not be repeated in this embodiment.
[0118] In summary, this utility model embodiment realizes a telecentric lens with a resolution of 145 lp / mm, a field of view of Φ300mm and above, a full field of view distortion of less than 0.02%, and supports full-frame cameras. This telecentric lens can significantly reduce the outer diameter of the lens after the first lens G1, effectively reducing the manufacturing cost and meeting the application requirements of precision detection or measurement.
[0119] 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 large field of view full-frame telecentric lens, characterized by, 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 positive refractive power, a fourth lens G4 having negative refractive power, a stop S, a fifth lens G5 having negative refractive power, a sixth lens G6 having positive refractive power, a seventh lens G7 having positive refractive power, and an eighth lens G8 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, the seventh lens G7, and the eighth lens G8 are all glass spherical lenses, and together form a double telecentric structure, wherein the first lens G1 has the largest outer diameter size. The third lens G3 and the fourth lens G4 form a cemented lens U1, and the fifth lens G5 and the sixth lens G6 form a cemented lens U2.
2. The optical system of a large field of view full format telecentric lens according to claim 1, wherein, The center distance between the first lens G1 and the second lens G2 is L1, the focal length of the first lens G1 is f1, the focal length of the second lens G2 is f2, and the focal length of the cemented lens group U1 is f U1 ; f1 and L1 satisfy the relationship: 0.9<|f1 / L1|<1.5; f U1 and f2satisfy the relationship: 0.4<|f U1 / f2|<0.
8.
3. The optical system of a large field of view full format telecentric lens according to claim 2, characterized in that, The center distance between the diaphragm S and the image plane is L2, and the focal length of the cemented lens group U2 is f U2 , the focal length of the seventh lens G7 is f7, and the focal length of the eighth lens G8 is f8; f U2 L2 satisfies the relationship: 0.24<|f U2 / L2|<0.65; f7 and L2 satisfy the relationship: 0.25<|f7 / L2|<0.6; f8 and L2 satisfy the relationship: 0.5<|f8 / L2|<0.
9.
4. The optical system of claim 3, wherein, The half image height of the optical system is y', and the half field of view is h; y' and h satisfy the relationship: |y' / h|<0.
5.
5. The optical system of a large field of view full format telecentric lens according to claim 1, wherein, The first lens G1 is a plano-convex lens, the second lens G2 is a meniscus lens, the third lens G3 is a meniscus lens, and the fourth lens G4 is a meniscus lens; the fifth lens G5 is a double-concave lens, the sixth lens G6 is a double-convex lens, the seventh lens G7 is a meniscus lens, and the eighth lens G8 is a double-convex lens.
6. The optical system of a large field of view full format telecentric lens according to claim 1, wherein, The ratio of the outer diameter size of the first lens G1 to the outer diameter size of the second lens G2 is greater than 3.
85.
7. The optical system of a large field of view full format telecentric lens according to claim 6, characterized in that, The outer diameter size of the cemented lens U1 and the outer diameter size of the cemented lens U2 are both smaller than the outer diameter size of the second lens G2.
8. The optical system of a large field of view full format telecentric lens according to claim 1, 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, and the eighth lens G8 are all on a predetermined optical axis; The stop S has a circular aperture, and the center of the circular aperture is on the predetermined optical axis.
9. A large field of view full format telecentric lens characterized in that, An optical system of a large field of view full-frame telecentric lens, comprising any one of the optical systems according to claims 1-8.