High-resolution low-distortion industrial lens and optical system thereof

Abstract

The invention relates to the technical field of optical imaging, and discloses a high-resolution low-distortion industrial lens and an optical system thereof. The optical system comprises a front group T1 with positive focal power, a diaphragm A0 and a rear group T2 with positive focal power, the front group T1 comprises a first lens group S1 with negative focal power, a second lens group S2 with positive focal power and a third lens group S3 with positive focal power; the distance between the vertex of the rear surface of the first lens group S1 and the vertex of the front surface of the third lens group S3 is DS, and the focal length f and DS of the optical system meet the relational expression that DS / f is larger than 0.90. According to the invention, a floating focusing mode is adopted, an optical system of an industrial lens with a focal length of 16mm is realized, the highest resolution can reach 185lp / mm, a 2.7 [mu] m pixel chip can be matched, the pixel can reach 24,000,000 pixels when the optical system corresponds to the maximum chip size, and the maximum optical distortion of a full view field is lower than 0.45%.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular, to a high-resolution and low-distortion industrial lens and its optical system. Background Art

[0002] With the upgrading of China's manufacturing industry and the improvement of automation level, the demand for high-resolution and low-distortion industrial lenses is increasing continuously. Industrial lenses are widely used in dimensional measurement, appearance inspection, defect detection, etc. of parts in fields such as automobile manufacturing, electronic manufacturing, and machinery manufacturing. For example, in the production of automobile parts, high-resolution and low-distortion industrial lenses can accurately detect the dimensions and surface defects of parts such as engine blocks and crankshafts to ensure product quality.

[0003] In recent years, image sensor technologies such as CMOS (Complementary Metal Oxide Semiconductor) and CCD (charge coupled device) have been continuously progressing, the number of pixels and the resolution have been continuously improved, and large-format image sensors have been gradually popularized. In order to give full play to the performance advantages of large-format image sensors, large-format industrial lenses that match them are required to achieve the best imaging effect. The combination of large-format industrial lenses and high-pixel image sensors can meet the requirements for large field of view and high-resolution imaging, and has promoted the development of industrial lenses in the direction of large format.

[0004] The design and manufacturing process requirements of large-format lenses are more complex, higher-quality optical materials and more precise processing equipment need to be used, resulting in higher manufacturing costs, relatively expensive prices, and increasing the overall cost of the system. At the same time, due to the large imaging area and complex optical structure of the lens, it is still relatively difficult to completely eliminate distortion, especially at the edge of the field of view, where a certain degree of distortion may occur, affecting the accuracy and stability of imaging. For this field, the existing lens designs can no longer meet the new industry requirements. Therefore, the research and development of high-resolution and low-distortion industrial lenses is more urgent.

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

[0006] The purpose of the present invention is to provide a high-resolution and low-distortion industrial lens and its optical system to solve or at least partially solve the technical problems existing in the prior art.

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

[0008] In a first aspect, the present invention provides an optical system for a high-resolution and low-distortion industrial lens, including a front group T1 with a positive optical power, a diaphragm A0, and a rear group T2 with a positive optical power, which are arranged in sequence from the object side to the image side;

[0009] The focal length of the optical system is f, the focal length of the front group T1 is f T1 , and the focal length of the rear group T2 is f T2 ; f and f T1 satisfy the relational expression: 0.95 < |f T1 / f| < 1.60; f and f T2 satisfy the relational expression: 1.40 < |f T2 / f| < 2.10;

[0010] The front group T1 includes a first lens group S1 with a negative optical power, a second lens group S2 with a positive optical power, and a third lens group S3 with a positive optical power, which are arranged in sequence from the object side to the image side; the distance between the vertex of the rear surface of the first lens group S1 and the vertex of the front surface of the third lens group S3 is D S , f and D S satisfy the relational expression: |D S / f| > 0.90;

[0011] The relative positions of the first lens group S1, the third lens group S3, and the rear group T2 with respect to the image plane all remain unchanged, and the second lens group S2 can be driven to move within the focusing region between the rear surface of the first lens group S1 and the front surface of the third lens group S3 along the optical axis of the optical system.

[0012] Optionally, the first lens group S1 includes a first lens G1 with a positive optical power, a second lens G2 with a negative optical power, a third lens G3 with a negative optical power, and a fourth lens G4 with a negative optical power;

[0013] The second lens group S2 includes a fifth lens G5 with a negative optical power, a sixth lens G6 with a positive optical power, and a seventh lens G7 with a positive optical power, where the fifth lens G5 and the sixth lens G6 are cemented into a first cemented lens group U1 with a positive optical power;

[0014] The third lens group S3 includes an eighth lens G8 with a positive optical power;

[0015] D S is the distance between the rear surface of the fourth lens G4 and the front surface of the eighth lens G8.

[0016] Optionally, the focal length of the first lens group S1 is f S1 , the focal length of the second lens group S2 is f S2 , and the focal length of the third lens group S3 is f S3 ;

[0017] f S1 The ratio with f satisfies the relation: 0.55 < |f S1 / f| < 1.00;

[0018] f S2 The ratio with f satisfies the relation: 1.00 < |f S2 / f| < 1.45;

[0019] f S3 The ratio with f satisfies the relation: 2.50 < |f S3 / f| < 6.00.

[0020] Optionally, the focal length of the first lens G1 is f G1 f G1 The ratio with f satisfies the relation: 2.40 < |f G1 / f| < 3.20;

[0021] The focal length of the second lens G2 is f G2 f G2 The ratio with f satisfies the relation: 1.20 < |f G2 / f| < 1.80;

[0022] The focal length of the third lens G3 is f G3 f G3 The ratio with f satisfies the relation: 0.90 < |f G3 / f| < 1.50;

[0023] The focal length of the fourth lens G4 is f G4 f G4 The ratio with f satisfies the relation: 5.00 < |f G4 / f| < 6.00;

[0024] The focal length of the first cemented lens group is f U1 f U1 The ratio with f satisfies the relation: 2.70 < |f U1 / f| < 3.20;

[0025] The focal length of the seventh lens G7 is f G7 f G7 The ratio with f satisfies the relation: 1.40 < |f G7 / f| < 2.00;

[0026] The focal length of the eighth lens G8 is f G8 f G8 The ratio with f satisfies the relation: 4.00 < |f G8 / f| < 5.00.

[0027] Optionally, in the first lens group S1, the first lens G1 and the second lens G2 are both meniscus lenses, and the third lens G3 and the fourth lens G4 are both biconcave lenses;

[0028] In the second lens group S2, the fifth lens G5 is a meniscus lens, and the sixth lens G6 and the seventh lens G7 are both biconvex lenses;

[0029] The eighth lens G8 is a biconvex lens.

[0030] Optionally, the rear group T2 includes a ninth lens G9 with a negative focal power, a tenth lens G10 with a positive focal power, an eleventh lens G11 with a positive focal power, and a twelfth lens G12 with a positive focal power, which are arranged in sequence from the object side to the image side. Among them, the ninth lens G9 and the tenth lens G10 are cemented into a second cemented lens group U2 with a negative focal power;

[0031] The focal length of the second cemented lens group is f U2 , f U2 and f satisfy the relationship: 1.00 < |f U2 / f| < 1.80;

[0032] The focal length of the eleventh lens G11 is f G11 , f G11 and f satisfy the relationship: 1.20 < |f G11 / f| < 1.80;

[0033] The focal length of the twelfth lens G12 is f G12 , f G12 and f satisfy the relationship: 3.00 < |f G12 / f| < 3.80.

[0034] Optionally, the ninth lens G9 is a biconcave lens, the tenth lens G10 and the eleventh lens G11 are both biconvex lenses, and the twelfth lens G12 is a meniscus lens.

[0035] Optionally, the first lens G1, the second lens G2, the third lens G13, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11, and the twelfth lens G12 are all glass spherical lenses.

[0036] Optionally, the optical axes of the first lens G1, the second lens G2, the third lens G13, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11, and the twelfth lens G12 all coincide with the optical axis of the optical system;

[0037] The aperture of the diaphragm A0 is a circular hole, and the center of the circular hole is on the optical axis of the optical system; the adjustment range of the aperture of the diaphragm A0 is from F2.8 to F16.

[0038] In a second aspect, the present invention provides a high-resolution and low-distortion industrial lens, including a focusing structure and an optical system of a high-resolution and low-distortion industrial lens as described above;

[0039] The focusing structure is used to drive the second lens group S2 to move along the optical axis of the optical system within the focusing region between the rear surface of the first lens group S1 and the front surface of the third lens group S3.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] Through the structural design of the above optical system, the present invention adopts a floating focusing method to achieve an optical system of an industrial lens with a focal length of 16 mm, with a maximum resolution of up to 185 lp / mm, which can be matched with a 2.7-micron pixel chip. When corresponding to the maximum chip size, its pixels can reach 24 million pixels, and the maximum optical distortion of the full field of view is less than 0.45%.

[0042] 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 accompanying drawings and specific embodiments are jointly used to explain the specific principles of the present invention. Description of the Drawings

[0043] 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 accompanying drawings required for 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.

[0044] Figure 1 It is a schematic structural diagram of an optical system of a high-resolution and low-distortion industrial lens provided by Embodiment 1 of the present invention.

[0045] Figure 2 It is an optical distortion curve diagram of an optical system of a high-resolution and low-distortion industrial lens provided by Embodiment 1 of the present invention. Detailed Embodiments

[0046] To describe in detail the possible application scenarios, technical principles, specific implementable solutions, achievable objectives and effects of this application, etc., the following will be elaborated in detail with reference to the specific examples listed and in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application, so they are only examples and cannot be used to limit the protection scope of this application.

[0047] Referring to "embodiment" in this document means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of this application. The term "embodiment" that appears 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 this application, as long as there is no technical contradiction or conflict, the various technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0048] Unless otherwise defined, the meanings of the technical terms used herein are the same as those commonly understood by those skilled in the technical field to which this application belongs; the use of the relevant terms herein is only to describe specific embodiments and is not intended to limit this application.

[0049] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that there can be three relationships. For example, A and / or B means: there is A, there is B, and there is both A and B at the same time. In addition, the character " / " in this document generally represents an "or" logical relationship between the associated objects before and after.

[0050] In this application, terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary-secondary or order relationship, etc. between these entities or operations.

[0051] Without more limitations, in this application, the expressions such as "include", "comprise", "have" or other similar expressions used in the statement are intended to cover non-exclusive inclusion. These expressions do not exclude that there may be other elements in the process, method or product including the said elements, so that the process, method or product including a series of elements may not only include those defined elements, but also include other elements not explicitly listed, or also include elements inherent to this process, method or product.

[0052] 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 base number; expressions such as "above", "below", and "within" are understood to include the base number. In addition, in the description of the embodiments of this application, the meaning of "multiple" is two or more (including two), and similar expressions related to "many" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise specifically defined.

[0053] In the description of the embodiments of this application, the spatially 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", "circumferential", etc., the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the specific embodiment or the drawings, and is only for the convenience of describing the specific embodiments of this application or for the reader to understand, 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, so it cannot be understood as a limitation on the embodiments of this application.

[0054] Unless otherwise clearly specified or limited, in the description of the embodiments of this application, the terms "installed", "connected", "connected", "fixed", "set", etc. should be understood in a broad sense. For example, the "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 components or the interaction relationship between two components. For those skilled in the art 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.

[0055] Embodiment 1:

[0056] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of an optical system of a high-resolution and low-distortion industrial lens provided by Embodiment 1 of the present invention.

[0057] As Figure 1 shown, the optical system includes:

[0058] The present invention provides an optical system of a high-resolution and low-distortion industrial lens, including a front group T1 with positive optical power, a diaphragm A0, and a rear group T2 with positive optical power, which are sequentially arranged from the object side to the image side;

[0059] The focal length f of the optical system, the focal length of the front group T1 is f T1 , and the focal length of the rear group T2 is fT2 ; f and f T1 satisfy the relationship: 0.95 < |f T1 / f| < 1.60; f and f T2 satisfy the relationship: 1.40 < |f T2 / f| < 2.10;

[0060] The front group T1 includes a first lens group S1 with negative optical power, a second lens group S2 with positive optical power, and a third lens group S3 with positive optical power, which are sequentially arranged from the object side to the image side; the distance between the vertex of the rear surface of the first lens group S1 and the vertex of the front surface of the third lens group S3 is D S , f and D S satisfy the relationship: |D S / f| > 0.90;

[0061] The relative positions of the first lens group S1, the third lens group S3, and the rear group T2 with respect to the image plane remain unchanged, and the second lens group S2 can be driven to move within the focusing region between the rear surface of the first lens group S1 and the front surface of the third lens group S3 along the optical axis of the optical system.

[0062] Optionally, the first lens group S1 includes a first lens G1 with positive optical power, a second lens G2 with negative optical power, a third lens G3 with negative optical power, and a fourth lens G4 with negative optical power;

[0063] The second lens group S2 includes a fifth lens G5 with negative optical power, a sixth lens G6 with positive optical power, and a seventh lens G7 with positive optical power, where the fifth lens G5 and the sixth lens G6 are cemented into a first cemented lens group U1 with positive optical power;

[0064] The third lens group S3 includes an eighth lens G8 with positive optical power;

[0065] D S is the distance between the rear surface of the fourth lens G4 and the front surface of the eighth lens G8.

[0066] Furthermore, the focal length of the first lens group S1 is f S1 , the focal length of the second lens group S2 is f S2 , the focal length of the third lens group S3 is f S3 ;

[0067] f S1 The ratio of f S1 to f satisfies the relationship: 0.55 < |f

[0068] f S2 to f satisfies the relationship: 1.00 < |f S2 / f | < 1.45;

[0069] f S3 The ratio with f satisfies the relationship: 2.50 < |f S3 / f | < 6.00.

[0070] Among them, the focal length of the first lens G1 is f G1 , f G1 and f satisfy the relationship: 2.40 < |f G1 / f | < 3.20;

[0071] The focal length of the second lens G2 is f G2 , f G2 and f satisfy the relationship: 1.20 < |f G2 / f | < 1.80;

[0072] The focal length of the third lens G3 is f G3 , f G3 and f satisfy the relationship: 0.90 < |f G3 / f | < 1.50;

[0073] The focal length of the fourth lens G4 is f G4 , f G4 and f satisfy the relationship: 5.00 < |f G4 / f | < 6.00;

[0074] The focal length of the first cemented lens group is f U1 , f U1 and f satisfy the relationship: 2.70 < |f U1 / f | < 3.20;

[0075] The focal length of the seventh lens G7 is f G7 , f G7 and f satisfy the relationship: 1.40 < |f G7 / f | < 2.00;

[0076] The focal length of the eighth lens G8 is f G8 , f G8 and f satisfy the relationship: 4.00 < |f G8 / f | < 5.00.

[0077] In this embodiment, in the first lens group S1, the first lens G1 and the second lens G2 are both meniscus lenses, and the third lens G3 and the fourth lens G4 are both biconcave lenses;

[0078] In the second lens group S2, the fifth lens G5 is a meniscus lens, and the sixth lens G6 and the seventh lens G7 are both biconvex lenses;

[0079] The eighth lens G8 is a biconvex lens.

[0080] Further, the rear group T2 includes a ninth lens G9 with a negative optical power, a tenth lens G10 with a positive optical power, an eleventh lens G11 with a positive optical power, and a twelfth lens G12 with a positive optical power, which are arranged in sequence from the object side to the image side. Among them, the ninth lens G9 and the tenth lens G10 are cemented to form a second cemented lens group U2 with a negative optical power;

[0081] The focal length of the second cemented lens group is f U2 , f U2 and f satisfy the relational expression: 1.00 < |f U2 / f| < 1.80;

[0082] The focal length of the eleventh lens G11 is f G11 , f G11 and f satisfy the relational expression: 1.20 < |f G11 / f| < 1.80;

[0083] The focal length of the twelfth lens G12 is f G12 , f G12 and f satisfy the relational expression: 3.00 < |f G12 / f| < 3.80.

[0084] In this embodiment, the ninth lens G9 is a biconcave lens, the tenth lens G10 and the eleventh lens G11 are both biconvex lenses, and the twelfth lens G12 is a meniscus lens.

[0085] Specifically, the first lens G1, the second lens G2, the third lens G13, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11, and the twelfth lens G12 are all glass spherical lenses.

[0086] Further, the optical axes of the first lens G1, the second lens G2, the third lens G13, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11, and the twelfth lens G12 all coincide with the optical axis of the optical system;

[0087] The aperture of the aperture stop A0 is a circular hole, and the center of the circular hole is on the optical axis of the optical system; the adjustment range of the aperture of the aperture stop A0 is F2.8 to F16. It can be understood that the aperture value of the aperture stop T needs to be adjusted correspondingly according to the specific application scenario.

[0088] To verify whether the above optical system meets the design purpose, the following is a specific application example given according to the above settings of this embodiment:

[0089] In this application example, the data of each lens of the optical system is shown in Table 1 below:

[0090] Table 1

[0091]

[0092]

[0093] It should be noted that in Table 1, the "front surface" corresponds to Figure 1 the left surface of the corresponding lens or lens group in Figure 1 and the "rear surface" corresponds to Figure 1 the right surface of the corresponding lens or lens group in Figure 1 ; or it can be understood that the object side is on the

[0094] left, the image side (or image plane) is on the T1 right, the surface closer to the object side is the "front surface", and the surface closer to the image side is the "rear surface". T2 In this example, the focal length f of the optical system is 16 mm, the maximum aperture is F# = 2.8, the focal length f S1 of the front group T1 is 21.87 mm, the focal length f S2 of the rear group T2 is 28.05 mm, the optical back focal length BFL = 16.80 mm, the semi-image height y' = 9.6 mm, the focal length f S3 of the first lens group S1 is -13.26 mm, the focal length f G1 of the second lens group S2 is 17.77 mm, the focal length f G2 of the third lens group S3 is 71.92 mm, the focal length f G3 of the first lens G1 is 45.86 mm, the focal length f G4 of the second lens G2 is -24.45 mm, the focal length f U1 of the third lens G3 is -19.81 mm, the focal length f G7 of the fourth lens G4 is -86.76 mm, the focal length f G8 of the first cemented lens group is 47.38 mm, the focal length f U2 of the seventh lens G7 is 27.78 mm, the focal length f G11 of the eighth lens G8 is 71.92 mm, the focal length f G12 of the second cemented lens group is -22.00 mm, the focal length f

[0095] Each relationship:

[0096] |f T1 / f| = 1.37; |fT2 |f| = 1.75; |L / f| = 4.20; |BFL / f| = 1.05;

[0097] |y’ / f| = 0.60; |f S1 |f| = 0.83; |f S2 |f| = 1.11; |f S3 |f| = 4.50;

[0098] |f G1 |f| = 2.87; |f G2 |f| = 1.53; |f G3 |f| = 1.24; |f G4 |f| = 5.42;

[0099] |f U1 |f| = 2.96; |f G7 |f| = 1.74; |f G8 |f| = 4.50; |f U2 |f| = 1.38;

[0100] |f G11 |f| = 1.51; |f G12 |f| = 3.41; |D S |f| = 1.45.

[0101] Satisfy the relationship:

[0102] 0.95 < |f T1 |f| < 1.60; 1.40 < |f T2 |f| < 2.10; |L / f| > 3.00;

[0103] |BFL / f| < 1.60; |y’ / f| < 0.85; 0.55 < |f S1 |f| < 1.00;

[0104] 1.00 < |f S2 |f| < 1.45; 2.50 < |f S3 |f| < 6.00;

[0105] 2.40 < |f G1 |f| < 3.20; 1.20 < |f G2 |f| < 1.80;

[0106] 0.90 < |f G3 |f| < 1.50; 5.00 < |f G4 |f| < 6.00;

[0107] 2.70 < |f U1 / f < 3.20; 1.40 < |f G7 / f < 2.00;

[0108] 4.00 < |f G8 / f < 5.00; 1.00 < |f U2 / f < 1.80;

[0109] 1.20 < |f G11 / f < 1.80; 3.00 < |f G12 / f < 3.80; |D S / f > 0.90。

[0110] Please refer to Figure 2 , Figure 2 the optical distortion curve graph of the optical system designed according to the above parameters, as Figure 2 shown, the maximum optical distortion of this optical system within the full field of view is less than 0.45%;

[0111] Through the above structure, this embodiment realizes an optical system of a low-distortion large-field-of-view macro lens with a focal length of 16 mm, the image-side F-number is 2.8, and the maximum imaging surface is The highest resolution can reach 185 lp / mm, which can match a 2.7-micron pixel chip. When corresponding to the maximum chip size, its pixels can reach 24 million pixels, and the maximum optical distortion of the full field of view is less than 0.45%; in addition, this optical system adopts a floating focusing method, and its light passing aperture can be flexibly adjusted.

[0112] Embodiment 2:

[0113] This embodiment provides a high-resolution low-distortion industrial lens, including a focusing structure and an optical system of a high-resolution low-distortion industrial lens as described in Embodiment 1;

[0114] The focusing structure is used to drive the second lens group S2 to move within the focusing area between the rear surface of the first lens group S1 and the front surface of the third lens group S3 along the optical axis of the optical system.

[0115] Specifically, as Figure 1 shown, this optical system includes a front group T1 with positive optical power, a diaphragm A0, and a rear group T2 with positive optical power arranged in sequence from the object side to the image side;

[0116] The focal length of this optical system is f, the focal length of the front group T1 is f T1 , and the focal length of the rear group T2 is f T2 ; f and f T1 satisfy the relationship: 0.95 < |f T1 / f| < 1.60; f and f T2 satisfy the relationship: 1.40 < |fT2 / f | < 2.10;

[0117] The front group T1 includes a first lens group S1 with negative optical power, a second lens group S2 with positive optical power, and a third lens group S3 with positive optical power, which are sequentially arranged from the object side to the image side; the distance between the vertex of the rear surface of the first lens group S1 and the vertex of the front surface of the third lens group S3 is D S , f and D S satisfy the relational expression: |D S / f| > 0.90;

[0118] The relative positions of the first lens group S1, the third lens group S3, and the rear group T2 with respect to the image plane remain unchanged, and the second lens group S2 can be driven to move within the focusing region between the rear surface of the first lens group S1 and the front surface of the third lens group S3 along the optical axis of the optical system.

[0119] Optionally, the first lens group S1 includes a first lens G1 with positive optical power, a second lens G2 with negative optical power, a third lens G3 with negative optical power, and a fourth lens G4 with negative optical power;

[0120] The second lens group S2 includes a fifth lens G5 with negative optical power, a sixth lens G6 with positive optical power, and a seventh lens G7 with positive optical power, where the fifth lens G5 and the sixth lens G6 are cemented into a first cemented lens group U1 with positive optical power;

[0121] The third lens group S3 includes an eighth lens G8 with positive optical power;

[0122] D S is the distance between the rear surface of the fourth lens G4 and the front surface of the eighth lens G8.

[0123] Furthermore, the focal length of the first lens group S1 is f S1 , the focal length of the second lens group S2 is f S2 , and the focal length of the third lens group S3 is f S3 ;

[0124] f S1 and the ratio of f satisfies the relational expression: 0.55 < |f S1 / f| < 1.00;

[0125] f S2 and the ratio of f satisfies the relational expression: 1.00 < |f S2 / f| < 1.45;

[0126] f S3 and the ratio of f satisfies the relational expression: 2.50 < |f S3 / f| < 6.00.

[0127] Specifically, the focal length of the first lens G1 is f G1 , f G1 and f satisfy the relationship: 2.40 < |f G1 / f| < 3.20;

[0128] The focal length of the second lens G2 is f G2 , f G2 and f satisfy the relationship: 1.20 < |f G2 / f| < 1.80;

[0129] The focal length of the third lens G3 is f G3 , f G3 and f satisfy the relationship: 0.90 < |f G3 / f| < 1.50;

[0130] The focal length of the fourth lens G4 is f G4 , f G4 and f satisfy the relationship: 5.00 < |f G4 / f| < 6.00;

[0131] The focal length of the first cemented lens group is f U1 , f U1 and f satisfy the relationship: 2.70 < |f U1 / f| < 3.20;

[0132] The focal length of the seventh lens G7 is f G7 , f G7 and f satisfy the relationship: 1.40 < |f G7 / f| < 2.00;

[0133] The focal length of the eighth lens G8 is f G8 , f G8 and f satisfy the relationship: 4.00 < |f G8 / f| < 5.00.

[0134] In this embodiment, in the first lens group S1, the first lens G1 and the second lens G2 are both meniscus lenses, and the third lens G3 and the fourth lens G4 are both biconcave lenses;

[0135] In the second lens group S2, the fifth lens G5 is a meniscus lens, and the sixth lens G6 and the seventh lens G7 are both biconvex lenses;

[0136] The eighth lens G8 is a biconvex lens.

[0137] Further, the rear group T2 includes a ninth lens G9 with a negative optical power, a tenth lens G10 with a positive optical power, an eleventh lens G11 with a positive optical power, and a twelfth lens G12 with a positive optical power, which are sequentially arranged from the object side to the image side. Among them, the ninth lens G9 and the tenth lens G10 are cemented to form a second cemented lens group U2 with a negative optical power;

[0138] The focal length of the second cemented lens group is f U2 , f U2 and f satisfy the relationship: 1.00 < |f U2 / f| < 1.80;

[0139] The focal length of the eleventh lens G11 is f G11 , f G11 and f satisfy the relationship: 1.20 < |f G11 / f| < 1.80;

[0140] The focal length of the twelfth lens G12 is f G12 , f G12 and f satisfy the relationship: 3.00 < |f G12 / f| < 3.80.

[0141] In this embodiment, the ninth lens G9 is a biconcave lens, the tenth lens G10 and the eleventh lens G11 are both biconvex lenses, and the twelfth lens G12 is a meniscus lens.

[0142] Specifically, the first lens G1, the second lens G2, the third lens G13, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11, and the twelfth lens G12 are all glass spherical lenses.

[0143] Further, the optical axes of the first lens G1, the second lens G2, the third lens G13, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11, and the twelfth lens G12 all coincide with the optical axis of the optical system;

[0144] The aperture of the aperture stop A0 is a circular hole, and the center of the circular hole is on the optical axis of the optical system; the adjustment range of the aperture of the aperture stop A0 is F2.8 to F16. It can be understood that the aperture value of the aperture stop T needs to be adjusted correspondingly according to the specific application scenario.

[0145] In summary, the embodiment of the present invention realizes an industrial lens with a focal length of 16 mm, high resolution and low distortion, which can meet the new industry requirements.

[0146] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting 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 described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical system of a high-resolution and low-distortion industrial lens, characterized in that It includes a front group T1 with positive optical power, a diaphragm A0, and a rear group T2 with positive optical power, which are arranged in sequence from the object side to the image side; The focal length f of the optical system, the focal length of the front group T1 is f T1 , and the focal length of the rear group T2 is f T2 ; f and f T1 satisfy the relationship: 0.95 < |f T1 / f| < 1.60; f and f T2 satisfy the relationship: 1.40 < |f T2 / f| < 2.10; The front group T1 includes a first lens group S1 with a negative focal power, a second lens group S2 with a positive focal power, and a third lens group S3 with a positive focal power, which are arranged in sequence from the object side to the image side; the distance between the vertex of the rear surface of the first lens group S1 and the vertex of the front surface of the third lens group S3 is D S , f and D S satisfy the relational expression: |D S / f| > 0.90; The relative positions of the first lens group S1, the third lens group S3, and the rear group T2 with respect to the image plane remain unchanged, and the second lens group S2 can be driven to move along the optical axis of the optical system within the focusing region between the rear surface of the first lens group S1 and the front surface of the third lens group S3.

2. The optical system of a high-resolution and low-distortion industrial lens according to claim 1, characterized in that, The first lens group S1 includes a first lens G1 with positive optical power, a second lens G2 with negative optical power, a third lens G3 with negative optical power, and a fourth lens G4 with negative optical power; The second lens group S2 includes a fifth lens G5 with negative optical power, a sixth lens G6 with positive optical power, and a seventh lens G7 with positive optical power. Among them, the fifth lens G5 and the sixth lens G6 are cemented into a first cemented lens group U1 with positive optical power; The third lens group S3 includes an eighth lens G8 with positive optical power; D S is the distance between the rear surface of the fourth lens G4 and the front surface of the eighth lens G8.

3. The optical system of a high-resolution and low-distortion industrial lens according to claim 2, characterized in that, The focal length of the first lens group S1 is f S1 , the focal length of the second lens group S2 is f S2 , the focal length of the third lens group S3 is f S3 ; f S1 The ratio with f satisfies the relation: 0.55 < |f S1 / f| < 1.00; f S2 The ratio with f satisfies the relationship: 1.00 < |f S2 / f| < 1.45; f S3 The ratio with f satisfies the relation: 2.50 < |f S3 / f| < 6.

00.

4. The optical system of a high-resolution and low-distortion industrial lens according to claim 3, characterized in that, The focal length of the first lens G1 is f G1 , f G1 and f satisfy the relationship: 2.40 < |f G1 / f| < 3.20; The focal length of the second lens G2 is f G2 , f G2 and f satisfy the relation: 1.20 < |f G2 / f| < 1.80; The focal length of the third lens G3 is f G3 , f G3 and f satisfy the relation: 0.90 < |f G3 / f| < 1.50; The focal length of the fourth lens G4 is f G4 , f G4 and f satisfy the relationship: 5.00 < |f G4 / f| < 6.00; The focal length of the first cemented lens group is f U1 , f U1 and f satisfy the relation: 2.70 < |f U1 / f| < 3.20; The focal length of the seventh lens G7 is f G7 , f G7 and f satisfy the relation: 1.40 < |f G7 / f| < 2.00; The focal length of the eighth lens G8 is f G8 , f G8 and f satisfy the relation: 4.00 < |f G8 / f| < 5.

00.

5. The optical system of a high-resolution and low-distortion industrial lens according to claim 4, characterized in that, In the first lens group S1, the first lens G1 and the second lens G2 are both meniscus lenses, and the third lens G3 and the fourth lens G4 are both biconcave lenses; In the second lens group S2, the fifth lens G5 is a meniscus lens, and the sixth lens G6 and the seventh lens G7 are both biconvex lenses; The eighth lens G8 is a biconvex lens.

6. The optical system of a high-resolution and low-distortion industrial lens according to claim 3, characterized in that, The rear group T2 includes a ninth lens G9 with negative optical power, a tenth lens G10 with positive optical power, an eleventh lens G11 with positive optical power, and a twelfth lens G12 with positive optical power, which are arranged in sequence from the object side to the image side. Among them, the ninth lens G9 and the tenth lens G10 are cemented into a second cemented lens group U2 with negative optical power; The focal length of the second cemented lens group is f U2 , f U2 and f satisfy the relationship: 1.00 < |f U2 / f| < 1.80; The focal length of the eleventh lens G11 is f G11 , f G11 and f satisfy the relation: 1.20 < |f G11 / f| < 1.80; The focal length of the twelfth lens G12 is f G12 , f G12 and f satisfy the relation: 3.00 < |f G12 / f| < 3.

80.

7. The optical system of a high-resolution and low-distortion industrial lens according to claim 6, characterized in that, The ninth lens G9 is a biconcave lens, the tenth lens G10 and the eleventh lens G11 are both biconvex lenses, and the twelfth lens G12 is a meniscus lens.

8. The optical system of a high-resolution and low-distortion industrial lens according to claim 7, characterized in that The first lens G1, the second lens G2, the third lens G13, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11, and the twelfth lens G12 are all glass spherical lenses.

9. The optical system of a high-resolution and low-distortion industrial lens according to claim 8, wherein The optical axes of the first lens G1, the second lens G2, the third lens G13, the fourth lens G4, the fifth lens G5, the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, the eleventh lens G11, and the twelfth lens G12 all coincide with the optical axis of the optical system; The aperture of the diaphragm A0 is a circular hole, and the center of the circular hole is on the optical axis of the optical system; the adjustment range of the aperture of the diaphragm A0 is F2.8 to F16.

10. A high-resolution and low-distortion industrial lens, characterized in that, It includes a focusing structure and an optical system of a high-resolution and low-distortion industrial lens as described in any one of claims 1-9; The focusing structure is used to drive the second lens group S2 to move along the optical axis of the optical system within the focusing region between the rear surface of the first lens group S1 and the front surface of the third lens group S3.

Images