Low-distortion large-target-surface industrial lens and optical system thereof

Abstract

The invention relates to the technical field of optical imaging, and discloses a low-distortion large-target-surface industrial lens and an optical system thereof. The optical system comprises a first lens group S1 with positive focal power, a diaphragm A0, a second lens group S2 with positive focal power and a third lens group S3 with positive focal power which are sequentially arranged from an object side to an image side, the first lens group S1, the second lens group S2 and the third lens group S3 are each composed of a plurality of spherical lenses, and the optical axes of all the spherical lenses coincide with a preset optical axis. According to the optical system provided by the invention, the highest resolution can reach 185lp / mm, the optical system can be matched with a 2.74 mu m pixel chip, the maximum optical distortion of a full view field is lower than 0.07%, and meanwhile, the optical system has the advantages of low distortion performance and high resolution.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to a low-distortion large-target-surface industrial lens and an optical system thereof. Background Art

[0002] With the promotion of intelligent manufacturing, the market demand for industrial lenses, as the core components of machine vision, continues to grow. As the "eyes" of the visual system, industrial lenses carry the key tasks of image capture and transmission, and their performance is directly related to the ultimate accuracy and stability of the visual system.

[0003] With the development of chip technology, the 1.2-inch camera chip market has shown a steady growth trend in recent years. 1.2-inch cameras are widely used in applications such as parts inspection, dimension measurement, position recognition, product assembly, and quality inspection. In order to meet the needs of new trends, the development of suitable 1.2-inch industrial lenses is imminent. In order to achieve accurate detection of tiny defects and changes and improve the accuracy and reliability of detection, the resolution of the industrial lens needs to reach 25 million, and under the premise of ensuring a large target surface, the corresponding optical distortion should also be as small as possible to meet the needs of high-precision detection.

[0004] In view of the above situation, for those skilled in the art, how to realize an industrial lens with low distortion and large target surface to adapt to the above application requirements has become a technical problem that needs to be solved urgently in this field.

[0005] The above information is presented as background information only to assist with understanding the present disclosure and no determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Summary of the invention

[0006] The object of the present invention is to provide a low-distortion large-target-area industrial lens and an optical system thereof, so as to solve or at least partially solve the technical problems existing in the prior art.

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

[0008] In a first aspect, the present invention provides an optical system of a low-distortion large-target-area industrial lens, comprising a first lens group S1 with positive focal power, an aperture A0, a second lens group S2 with positive focal power, and a third lens group S3 with positive focal power, which are sequentially arranged from the object side to the image side; the first lens group S1, the second lens group S2, and the third lens group S3 are respectively composed of a plurality of spherical lenses, and the optical axes of all the spherical lenses coincide with a predetermined optical axis;

[0009] The focal length of the optical system is f, and 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 、f S2 、f S3 And f respectively satisfy the following relations:

[0010] 1.60<|f S1 / f|<2.10, 0.70<|f S2 / f|<1.30, 2.10<|f S3 / f|<3.20.

[0011] Optionally, the relative position between the first lens group S1 and the aperture A0 remains unchanged, the relative position between the aperture A0 and the second lens group S2 remains unchanged, and the relative position between the third lens group S3 and the image plane of the optical system remains unchanged;

[0012] The air space DS between the second lens group S2 and the third lens group S3 can be adjusted. The ratio of the air space DS to the focal length f of the optical system must satisfy the relationship:

[0013] |DS / f|<0.60.

[0014] Optionally, the first lens group S1 includes a first lens G1 with positive refractive power, a second lens G2 with positive refractive power, and a third lens G3 with negative refractive power, which are sequentially arranged from the object side to the image side;

[0015] The second lens group S2 includes a fourth lens G4 with negative refractive power, a fifth lens G5 with positive refractive power, and a sixth lens G6 with positive refractive power, which are arranged in sequence from the object side to the image side;

[0016] The third lens group S3 includes a seventh lens G7 with positive refractive power and an eighth lens G8 with negative refractive power, which are arranged in sequence from the object side to the image side;

[0017] The aperture A0 is disposed between the third lens G3 and the fourth lens G4;

[0018] Among them, the first lens G1, the sixth lens G6 and the eighth lens G8 are all meniscus lenses, the second lens G2 is a biconvex lens or a meniscus lens, the third lens G3 is a biconcave lens or a meniscus lens, the fourth lens G4 is a biconcave lens, the fifth lens G5 and the seventh lens G7 are biconvex lenses,

[0019] Optionally, the second lens G2 and the third lens G3 are cemented into a first cemented lens group U1 with negative power; the fourth lens G4 and the fifth lens G5 are cemented into a second cemented lens group U2 with negative power; the seventh lens G7 and the eighth lens G8 are cemented into a third cemented lens group U3 with positive power;

[0020] The focal length of the first lens G1 is f G1 , its focal length f G1 The ratio of the focal length f of the optical system satisfies the relationship: 1.00<|f G1 / f|<1.60;

[0021] The focal length of the first cemented lens group is f U1 , its focal length f U1 The ratio of the focal length f of the optical system satisfies the relationship: 1.40<|f U1 / f|<2.20;

[0022] The focal length of the second cemented lens group is f U2 , its focal length f U2 The ratio of the focal length f of the optical system satisfies the relationship: 1.70<|f U2 / f|<2.60;

[0023] The focal length of the sixth lens G6 is f G6 , its focal length f G6 The ratio of the focal length f of the optical system satisfies the relationship: 0.60<|f G6 / f|<1.30.

[0024] Optionally, the distance L from the front surface vertex of the first lens G1 of the optical system to the back surface vertex of the eighth lens G8 and the focal length f of the optical system need to satisfy the relationship:

[0025] |L / f|>0.80.

[0026] Optionally, the optical back focal length BFL of the optical system and the focal length f of the optical system satisfy the relationship:

[0027] |BFL / f|<0.60.

[0028] Optionally, the half-image height y' of the optical system and the focal length f of the optical system satisfy the relationship:

[0029] |y' / f|<0.30.

[0030] Optionally, the aperture of the aperture A0 is set as a circular hole, and the center of the circular hole is on the predetermined optical axis;

[0031] The aperture value of aperture A0 can be adjusted, and the adjustment range of the aperture value is F2.8 to F16.

[0032] In a second aspect, the present invention provides a low-distortion large-target-surface industrial lens, comprising a focusing structure and an optical system of the low-distortion large-target-surface industrial lens as described above;

[0033] The focusing structure can drive the first lens group S1, the aperture A0 and the second lens group S2 as a whole to move closer to or farther from the third lens group S3 along a predetermined optical axis to make the image clear.

[0034] Optionally, the focal length f of the optical system is 50 mm.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The optical system provided by the present invention has a maximum resolution of up to 185lp / mm, can match a 2.74μm pixel chip, and has a maximum optical distortion of less than 0.07% in the entire field of view, and has the advantages of low distortion performance and high resolution.

[0037] The present invention has other features and advantages, which will be apparent from or will be described in detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 The present invention is a schematic structural diagram of an optical system of a low-distortion large-target-area industrial lens provided in an embodiment of the present invention.

[0040] Figure 2 The optical distortion curve of the optical system of a low-distortion large-target-area industrial lens provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0042] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0043] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0044] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0045] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0046] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0047] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0048] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0049] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms such as "install", "connect", "connect", "fix", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For technicians in the technical field to which the present application belongs, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0050] Embodiment 1:

[0051] See also Figure 1 , Figure 1 It is a schematic structural diagram of an optical system of a low-distortion large-target-surface industrial lens provided by an embodiment of the present invention;

[0052] like Figure 1 As shown, the optical system comprises a first lens group S1 with positive focal power, an aperture A0, a second lens group S2 with positive focal power and a third lens group S3 with positive focal power, which are arranged in sequence from the object side to the image side; the first lens group S1, the second lens group S2 and the third lens group S3 are respectively composed of a plurality of spherical lenses, and the optical axes of all the spherical lenses coincide with the predetermined optical axis;

[0053] The focal length of the optical system is f, the focal length of the first lens group S1 is fS1, the focal length of the second lens group S2 is fS2, and the focal length of the third lens group S3 is fS3; fS1, fS2, fS3 and f respectively satisfy the following relationships:

[0054] 1.60<|fS1 / f|<2.10, 0.70<|fS2 / f|<1.30, 2.10<|fS3 / f|<3.20.

[0055] It should be noted that the object is located at Figure 1On the left side of the first lens group S1, the image side (or image plane) is located Figure 1 The right side of the third lens group S3; Figure 1 The dotted line in the middle is the optical axis of the optical system.

[0056] Furthermore, in this embodiment, the relative position between the first lens group S1 and the aperture A0 remains unchanged, the relative position between the aperture A0 and the second lens group S2 remains unchanged, and the relative position between the third lens group S3 and the image plane of the optical system remains unchanged;

[0057] The air space DS between the second lens group S2 and the third lens group S3 can be adjusted. The ratio of the air space DS to the focal length f of the optical system must satisfy the relationship:

[0058] |DS / f|<0.60.

[0059] The focusing operation of the optical system is specifically implemented as follows: the air space DS is adjusted by driving the first lens group S1, the aperture A0 and the second lens group S2 to move as a whole, thereby making the image clear.

[0060] Specifically, the first lens group S1 includes a first lens G1 with positive refractive power, a second lens G2 with positive refractive power, and a third lens G3 with negative refractive power, which are arranged in sequence from the object side to the image side;

[0061] The second lens group S2 includes a fourth lens G4 with negative refractive power, a fifth lens G5 with positive refractive power, and a sixth lens G6 with positive refractive power, which are arranged in sequence from the object side to the image side;

[0062] The third lens group S3 includes a seventh lens G7 with positive refractive power and an eighth lens G8 with negative refractive power, which are arranged in sequence from the object side to the image side;

[0063] The aperture A0 is provided between the third lens G3 and the fourth lens G4.

[0064] Illustratively, in this embodiment, the first lens G1, the sixth lens G6 and the eighth lens G8 are all meniscus lenses, the second lens G2 is a biconvex lens or a meniscus lens, the third lens G3 is a biconcave lens or a meniscus lens, the fourth lens G4 is a biconcave lens, and the fifth lens G5 and the seventh lens G7 are biconvex lenses.

[0065] As an optional implementation, the second lens G2 and the third lens G3 are cemented into a first cemented lens group U1 with negative power; the fourth lens G4 and the fifth lens G5 are cemented into a second cemented lens group U2 with negative power; the seventh lens G7 and the eighth lens G8 are cemented into a third cemented lens group U3 with positive power;

[0066] Furthermore, the focal length of the first lens G1 is f G1 , its focal length f G1 The ratio of the focal length f of the optical system satisfies the relationship: 1.00<|f G1 / f|<1.60;

[0067] The focal length of the first cemented lens group is f U1 , its focal length f U1 The ratio of the focal length f of the optical system satisfies the relationship: 1.40<|f U1 / f|<2.20;

[0068] The focal length of the second cemented lens group is f U2 , its focal length f U2 The ratio of the focal length f of the optical system satisfies the relationship: 1.70<|f U2 / f|<2.60;

[0069] The focal length of the sixth lens G6 is f G6 , its focal length f G6 The ratio of the focal length f of the optical system satisfies the relationship: 0.60<|f G6 / f|<1.30.

[0070] More specifically, the distance L from the front surface vertex of the first lens G1 of the optical system to the back surface vertex of the eighth lens G8 and the focal length f of the optical system must satisfy the relationship:

[0071] |L / f|>0.80.

[0072] The optical back focal length BFL of the optical system and the focal length f of the optical system satisfy the relationship:

[0073] |BFL / f|<0.60.

[0074] The half-image height y' of the optical system and the focal length f of the optical system satisfy the relationship:

[0075] |y' / f|<0.30.

[0076] More specifically, the aperture of the aperture A0 is set as a circular hole, and the center of the circular hole is on the predetermined optical axis;

[0077] In this embodiment, the aperture value of the aperture A0 can be adjusted, and the adjustment range of the aperture value is F2.8 to F16.

[0078] Exemplarily, in this example, the optical system data is specifically shown in Table 1:

[0079] Table 1

[0080]

[0081]

[0082] It should be noted that in Table 1, the “front surface” corresponds to Figure 1 The left side surface of the lens or lens group corresponds to the "back surface" Figure 1 corresponds to the right side surface of a lens or lens group; that is, "front" corresponds to Figure 1 On the left side, "after" corresponds to Figure 1 on the left side.

[0083] In this example, in this example, the focal length f of the optical system is 50 mm, the maximum aperture is F2.8, and the focal length f of the first lens group S1 is S1 =91.40mm, the focal length of the second lens group S2 is f S2 =51.50mm, the focal length of the third lens group S3 is f S3 =139.60mm;

[0084] The distance L from the front surface vertex of the first lens G1 to the back surface vertex of the eighth lens G8 is 48.13 mm, the optical back focal length BFL is 21.70 mm, the half image height y' is 9.65 mm, and the focal length f of the first lens G1 is G1 =63.96mm, the focal length of the first cemented lens group is f U1 =-85.10mm, the focal length of the second cemented lens group is f U2 =-106.70mm, the focal length of the sixth lens G6 is f G6 =40.50mm;

[0085] Air spacing DS∈(2.00,20.00)mm.

[0086] Substituting the above values ​​into each relational expression, we obtain:

[0087] |f S1 / f|=1.83;|f S2 / f|=1.03;|f S3 / f|=2.79; |L / f|=0.96;

[0088] |BFL / f|=0.43; |y' / f|=0.19; |f G1 / f|=1.28;|f U1 / f|=1.70;

[0089] |f U2 / f|=2.13;|f G6 / f|=0.81; 0.04<|DS / f|<0.40.

[0090] The obtained values ​​satisfy the respective relationships, as shown below:

[0091] 1.60<|f S1 / f|<2.10; 0.70<|f S2 / f|<1.30; 2.10<|f S3 / f|<3.20;

[0092] |L / f|>0.80; |BFL / f|<0.60; |y' / f|<0.30;

[0093] 1.00<|f G1 / f|<1.60;1.40<|f U1 / f|<2.20;

[0094] 1.70<|f U2 / f|<2.60;0.60<|f G6 / f|<1.30; |DS / f|<0.60.

[0095] Please continue to refer to Figure 2 , Figure 2 It is an optical distortion curve of an optical system of an industrial lens with low distortion and large target surface provided by an embodiment of the present invention;

[0096] The optical system provided in this embodiment has a maximum resolution of up to 185lp / mm, can match a 2.74μm pixel chip, and has a maximum optical distortion of less than 0.07% in the entire field of view. In addition, the optical system adopts a floating focus method, and its aperture can be flexibly adjusted.

[0097] Embodiment 2:

[0098] This embodiment provides a low-distortion large-target-area industrial lens, comprising a focusing structure and an optical system of a low-distortion large-target-area industrial lens as described in Embodiment 1;

[0099] The focusing structure is used to drive the first lens group S1, the aperture A0 and the second lens group S2 as a whole along a predetermined optical axis to move closer to or farther from the third lens group S3 to achieve focusing.

[0100] Since the optical system has been described in detail in the first embodiment, it will not be described in detail in this embodiment.

[0101] In summary, the embodiment of the present invention realizes a low-distortion optical industrial lens with a focal length of 50mm, an image side F number of 2.8, a maximum imaging surface of φ19.3mm, a maximum resolution of up to 185lp / mm, and can match a 2.74μm pixel chip. When the corresponding maximum chip size is used, its pixels can reach 25 million pixels, and the maximum optical distortion of the full field of view is less than 0.07%; in addition, the industrial lens adopts a floating focus method, and its aperture can also be flexibly adjusted.

[0102] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical system of a low-distortion large-target-area industrial lens, characterized in that: The lens comprises a first lens group S1 with positive refractive power, an aperture A0, a second lens group S2 with positive refractive power and a third lens group S3 with positive refractive power, which are arranged in sequence from the object side to the image side; the first lens group S1, the second lens group S2 and the third lens group S3 are respectively composed of a plurality of spherical lenses, and the optical axes of all the spherical lenses coincide with the predetermined optical axis; The focal length of the optical system is f, and 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 、f S2 、f S3 And f respectively satisfy the following relations: 1.60<|f S1 / f|<2.10,0.70<|f S2 / f|<1.30,2.10<|f S3 / f|<3.20。 2. The optical system of a low-distortion large-target-area industrial lens according to claim 1, characterized in that: The relative position between the first lens group S1 and the aperture A0 remains unchanged, the relative position between the aperture A0 and the second lens group S2 remains unchanged, and the relative position between the third lens group S3 and the image plane of the optical system remains unchanged; The air space DS between the second lens group S2 and the third lens group S3 can be adjusted. The ratio of the air space DS to the focal length f of the optical system must satisfy the relationship: |DS / f|<0.

60.

3. The optical system of a low-distortion large-target-area industrial lens according to claim 2, characterized in that: The first lens group S1 includes a first lens G1 with positive refractive power, a second lens G2 with positive refractive power, and a third lens G3 with negative refractive power, which are arranged in sequence from the object side to the image side; The second lens group S2 includes a fourth lens G4 with negative refractive power, a fifth lens G5 with positive refractive power, and a sixth lens G6 with positive refractive power, which are arranged in sequence from the object side to the image side; The third lens group S3 includes a seventh lens G7 with positive refractive power and an eighth lens G8 with negative refractive power, which are arranged in sequence from the object side to the image side; The aperture A0 is disposed between the third lens G3 and the fourth lens G4; Among them, the first lens G1, the sixth lens G6 and the eighth lens G8 are all meniscus lenses, the second lens G2 is a biconvex lens or a meniscus lens, the third lens G3 is a biconcave lens or a meniscus lens, the fourth lens G4 is a biconcave lens, and the fifth lens G5 and the seventh lens G7 are biconvex lenses.

4. The optical system of a low-distortion large-target-area industrial lens according to claim 3, characterized in that: The second lens G2 and the third lens G3 are cemented into a first cemented lens group U1 having negative power; The fourth lens G4 and the fifth lens G5 are cemented into a second cemented lens group U2 with negative power; the seventh lens G7 and the eighth lens G8 are cemented into a third cemented lens group U3 with positive power; The focal length of the first lens G1 is f G1 , its focal length f G1 The ratio of the focal length f of the optical system satisfies the relationship: 1.00<|f G1 / f|<1.60; The focal length of the first cemented lens group is f U1 , its focal length f U1 The ratio of the focal length f of the optical system satisfies the relationship: 1.40<|f U1 / f|<2.20; The focal length of the second cemented lens group is f U2 , its focal length f U2 The ratio of the focal length f of the optical system satisfies the relationship: 1.70<|f U2 / f|<2.60; The focal length of the sixth lens G6 is f G6 , its focal length f G6 The ratio of the focal length f of the optical system satisfies the relationship: 0.60<|f G6 / f|<1.

30.

5. The optical system of a low-distortion large-target-area industrial lens according to claim 1, characterized in that: The distance L from the front surface vertex of the first lens G1 of the optical system to the back surface vertex of the eighth lens G8 and the focal length f of the optical system must satisfy the relationship: |L / f|>0.

80.

6. The optical system of a low-distortion large-target-area industrial lens according to claim 1, characterized in that: The optical back focal length BFL of the optical system and the focal length f of the optical system satisfy the relationship: |BFL / f|<0.

60.

7. The optical system of a low-distortion large-target-area industrial lens according to claim 1, characterized in that: The half-image height y' of the optical system and the focal length f of the optical system satisfy the relationship: |y' / f|<0.

30.

8. The optical system of a low-distortion large-target-area industrial lens according to claim 1, characterized in that: The aperture of the aperture A0 is set as a circular hole, and the center of the circular hole is on the predetermined optical axis; The aperture value of aperture A0 can be adjusted, and the adjustment range of the aperture value is F2.8 to F16.

9. A low-distortion large-target-area industrial lens, characterized in that: An optical system comprising a focusing structure and a low-distortion large-target-surface industrial lens as claimed in any one of claims 1 to 8; The focusing structure can drive the first lens group S1, the aperture A0 and the second lens group S2 as a whole to move closer to or farther from the third lens group S3 along a predetermined optical axis.

10. The low-distortion large-target-area industrial lens according to claim 9, characterized in that: The focal length f of the optical system is 50 mm.

Images