A large-surface, high-resolution industrial lens and its optical system

Abstract

The application relates to the field of optical imaging technology and discloses a large-target high-resolution industrial lens and an optical system thereof. The optical system comprises, arranged in sequence from an object side to an image side, 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, and the relative positions of the third lens group S3 and the image plane of the optical system remain unchanged; 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. The optical system provided by the application has a maximum resolution of 185 lp / mm, can match a 2.74-micron pixel chip, has a maximum target size of 1.2 inches, and has the advantages of low distortion performance and wide working distance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical imaging technology, and in particular to a large target surface high-resolution industrial lens and an optical system thereof. BACKGROUND

[0002] With the rise of intelligent manufacturing and the deep integration of industrial internet, the industrial lens industry has ushered in unprecedented development opportunities. As the core component of the machine vision system, the industrial lens carries the key task of image capture and transmission, and its performance is directly related to the efficiency and accuracy of the automated production line.

[0003] On the one hand, the improvement of detection level puts forward higher requirements for machine vision lenses; small space occupation, large target surface support, and high image quality are the development trend. On the other hand, with the development of chip technology, the 1.2-inch camera chip market has shown a steady growth trend in recent years. The target surface of the new generation of chips is expanded to 1.2 inches, and the chip pixel size is also reduced to 2.74um, which makes the camera have a significant improvement in imaging quality and performance. In order to meet the new trend demand, developing a machine vision lens that supports large target surface sensor chips, low distortion, and high resolution has become a technical problem to be solved in the field.

[0004] The above information is given as background information only to assist with understanding the present disclosure and does not establish any admission or recognition that any of the imaginary above is applicable as prior art with respect to the present disclosure. SUMMARY

[0005] The purpose of the present application is to provide a large target surface high-resolution industrial lens and an optical system thereof to solve or at least partially solve the technical problems existing in the prior art.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides an optical system of a large target surface high-resolution 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 arranged in order 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;

[0008] The focal length f of the optical system, the focal length f S1 of the first lens group S1, the focal length f S2 of the second lens group S2 and the focal length f S3 of the third lens group S3 respectively satisfy the following relationship:

[0009] 1.10<|f S1|f| < 1.90;

[0010] 1.00<|f S2 |f| < 1.60;

[0011] 1.40<|f S3 |f| < 2.00.

[0012] Optionally, the relative positions of the first lens group S1 and the stop A0 remain unchanged, the relative positions of the stop A0 and the second lens group S2 remain unchanged, and the relative positions of the third lens group S3 and the image plane of the optical system remain unchanged.

[0013] The air gap DS between the second lens group S2 and the third lens group S3 can be adjusted, and the ratio of the air gap DS to the focal length f of the optical system satisfies the relationship:

[0014] |DS / f| < 0.55.

[0015] Optionally, the first lens group S1 includes, in order from the object side to the image side, a first lens G1 with negative optical power, a second lens G2 with positive optical power, a third lens G3 with positive optical power, and a fourth lens G4 with negative optical power.

[0016] The second lens group S2 includes, in order from the object side to the image side, a fifth lens G5 with negative optical power, a sixth lens G6 with positive optical power, a seventh lens G7 with negative optical power, and an eighth lens G8 with positive optical power.

[0017] The third lens group S3 includes a ninth lens G9 with positive optical power.

[0018] The stop A0 is arranged between the fourth lens G4 and the fifth lens G5.

[0019] Optionally, the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, and the seventh lens G7 are all crescent lenses; the eighth lens G8 and the ninth lens G9 are double convex lenses.

[0020] Optionally, the first lens G1 and the second lens G2 are cemented into a first cemented lens group U1 with positive optical power; the third lens G3 and the fourth lens G4 are cemented into a second cemented lens group U2 with positive optical power; the fifth lens G5, the sixth lens G6, and the seventh lens G7 are cemented into a third cemented lens group U3 with negative optical power.

[0021] The focal length of the first cemented lens group U1 is f U1 , and the ratio of the focal length f of the optical system satisfies the relationship:

[0022] 1.80 < |fU1 |f | < 2.50;

[0023] The focal length of the second cemented lens group U2 is f U2 , and the ratio of the focal length of the optical system f satisfies the relationship:

[0024] 3.50 < |f U2 |f | < 9.50;

[0025] The focal length of the third cemented lens group U3 is f U3 , and the ratio of the focal length of the optical system f satisfies the relationship:

[0026] 2.50 < |f U3 |f | < 6.50;

[0027] The focal length of the eighth lens G8 is f G8 , and the ratio of the focal length of the optical system f satisfies the relationship: 1.00 < |f G8 |f | < 1.60.

[0028] Optionally, the distance L between the front surface vertex of the first lens G1 and the rear surface vertex of the ninth lens G9 and the focal length of the optical system f satisfy the relationship:

[0029] |L / f| > 1.05.

[0030] Optionally, the optical back focal length BFL of the optical system and the focal length of the optical system f satisfy the relationship:

[0031] |BFL / f| < 0.55.

[0032] Optionally, the half image height y' of the optical system and the focal length of the optical system f satisfy the relationship:

[0033] |y' / f| < 0.40.

[0034] Optionally, the aperture of the diaphragm A0 is set as a circular hole, and the center of the circular hole is on the predetermined optical axis;

[0035] The aperture value of the diaphragm A0 can be adjusted, and the adjustment range of the aperture value is F2.8~F16.

[0036] In a second aspect, the present application provides a large target surface high resolution industrial lens, comprising a focusing structure and a large target surface high resolution industrial lens optical system as described above;

[0037] The focusing structure is used to drive the first lens group S1, the diaphragm A0 and the second lens group S2 as a whole to move together along the predetermined optical axis to approach or move away from the third lens group S3, so as to make the image clear.

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] The optical system provided by the present application has a maximum resolution of 185 lp / mm, can match a 2.74-micron pixel chip, has a maximum target surface size of 1.2", and has the advantages of low distortion performance and wide working distance.

[0040] The present application has other characteristics and advantages, which will be apparent from or set forth in the accompanying drawings and subsequent detailed description, which together serve to explain certain principles of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings required by the embodiments or the prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these accompanying drawings without creative labor.

[0042] Figure 1 is a structural schematic diagram of an optical system of a large-target high-resolution industrial lens provided by an embodiment of the present application.

[0043] Figure 2 is an optical distortion curve of an optical system of a large-target high-resolution industrial lens provided by an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings required by the embodiments or the prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these accompanying drawings without creative labor.

[0045] In this document, the term "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing at various places in the specification does not necessarily refer to the same embodiment, and does not particularly limit the independence or association between other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, each technical feature mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.

[0046] Unless otherwise defined, the meanings of technical terms used in the present application are the same as those commonly understood by one skilled in the art to which the present application belongs; the use of related terms herein is only for the purpose of describing specific embodiments of the present application, and is not intended to limit the present application.

[0047] In the description of the present application, the phrase "and / or" is a description of a logical relationship between objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character " / " herein generally represents that the associated objects before and after are a "or" logical relationship.

[0048] In the present application, the phrases 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 and secondary, or order relationship between the entities or operations.

[0049] In the present application, the phrases "include", "contain", "have" or other similar expressions used in the sentence are intended to cover non-exclusive inclusion, and these expressions do not exclude the presence of other elements in the process, method or product including the described elements, so that the process, method or product including a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0050] As the same as the understanding in the "Guidelines for Examination", in the present application, the expressions such as "greater than", "less than", "exceed" are understood as not including the number; the expressions such as "above", "below", "within" are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is more than two (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times" and the like, unless otherwise explicitly limited.

[0051] In the description of the embodiments of the present application, the spatial-related expressions used, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "perpendicular", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or the drawings, and are only for the convenience of describing the specific embodiments of the present application or for the reader to understand, and are not intended to indicate or imply that the indicated 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.

[0052] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "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 an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances. Example 1:

[0053] See also Figure 1 , Figure 1 This is a schematic structural diagram of an optical system of a large-surface, high-resolution industrial lens provided by an embodiment of the present invention;

[0054] like Figure 1 As shown, the optical system includes 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;

[0055] The focal length f of the optical system, the focal length f of the first lens group S1 S1 , the focal length f of the second lens group S2 S2 and the focal length f of the third lens group S3 S3 The following relationships are satisfied:

[0056] 1.10<|f S1 / f|<1.90;

[0057] 1.00<|f S2 / f|<1.60;

[0058] 1.40<|f S3 / f|<2.00.

[0059] It should be noted that the object is located in Figure 1 On the left side of the first lens group S1, the image side (or image plane) is located Figure 1 On the right side of the third lens group S3.

[0060] Furthermore, in this embodiment, the relative positions of the third lens group S3 and the image plane of the optical system remain unchanged, the relative positions of the first lens group S1 and the aperture A0 remain unchanged, and the relative positions of the aperture A0 and the second lens group S2 remain unchanged.

[0061] The air gap DS between the second lens group S2 and the third lens group S3 can be adjusted, and the ratio of the air gap DS to the focal length f of the optical system satisfies the relationship:

[0062] |DS / f|<0.55.

[0063] The focusing operation of the optical system is specifically implemented by driving the first lens group S1, the diaphragm A0 and the second lens group S2 to move together as a whole to adjust the air gap DS, and then to make the image clear.

[0064] Specifically, the first lens group S1 includes a first lens G1 with negative focal power, a second lens G2 with positive focal power, a third lens G3 with positive focal power, and a fourth lens G4 with negative focal power arranged in order from the object side to the image side;

[0065] The second lens group S2 includes a fifth lens G5 with negative focal power, a sixth lens G6 with positive focal power, a seventh lens G7 with negative focal power, and an eighth lens G8 with positive focal power arranged in order from the object side to the image side;

[0066] The third lens group S3 includes a ninth lens G9 with positive focal power;

[0067] The diaphragm A0 is arranged between the fourth lens G4 and the fifth lens G5.

[0068] For example, in the 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 and the seventh lens G7 are all crescent lenses; the eighth lens G8 and the ninth lens G9 are double convex lenses.

[0069] As an optional embodiment, the first lens G1 and the second lens G2 are glued into a first glued lens group U1 with positive focal power; the third lens G3 and the fourth lens G4 are glued into a second glued lens group U2 with positive focal power; the fifth lens G5, the sixth lens G6 and the seventh lens G7 are glued into a third glued lens group U3 with negative focal power;

[0070] Further, the focal length of the first glued lens group U1 is f U1 , and the ratio of the focal length f of the optical system satisfies the relationship:

[0071] 1.80<|f U1 / f|<2.50;

[0072] The focal length of the second glued lens group U2 is f U2 , and the ratio of the focal length f of the optical system satisfies the relationship:

[0073] 3.50<|fU2 |f / f| < 9.50;

[0074] The focal length of the third cemented lens group U3 is f U3 , and the ratio of the focal length of the optical system f satisfies the relationship:

[0075] 2.50 < |f U3 | < 6.50.

[0076] The focal length of the eighth lens G8 is f G8 , and the ratio of the focal length of the optical system f satisfies the relationship:

[0077] 1.00 < |f G8 | < 1.60.

[0078] More specifically, the distance L between the vertex of the front surface of the first lens G1 and the vertex of the rear surface of the ninth lens G9 and the focal length of the optical system f satisfy the relationship:

[0079] |L / f| > 1.05.

[0080] The optical back focal length BFL of the optical system and the focal length of the optical system f satisfy the relationship:

[0081] |BFL / f| < 0.55.

[0082] The half image height y' of the optical system and the focal length of the optical system f satisfy the relationship:

[0083] |y' / f| < 0.40.

[0084] More specifically, the aperture of the diaphragm A0 is set as a circular hole, and the center of the circular hole is on the predetermined optical axis;

[0085] In this embodiment, the aperture value of the diaphragm A0 can be adjusted, and the adjustment range of the aperture value is F2.8~F16.

[0086] For example, in this example, the optical system data is as shown in Table 1:

[0087] Table 1

[0088] Surface Radius (mm) Thickness (mm) Refractive index U1 front surface 33.5 1.5 1.7 U1 cemented surface 15.3 5.0 1.7 U1 rear surface 76.5 4.2 U2 front surface 14.0 3.1 2.0 U2 cemented surface 39.7 1.8 1.6 U2 rear surface 9.2 5.0 Diaphragm Plane 6.9 U3 front surface -10.2 1.5 1.7 U3 first cemented surface -136.1 4.3 1.8 U3 second cemented surface -9.9 1.5 1.8 U3 rear surface -16.5 0.1 G8 front surface 105.5 2.8 1.8 G8 rear surface -66.6 4.3 G9 front surface 62.6 2.6 1.8 G9 rear surface -337.3 12.8 Image surface Plane

[0089] It should be noted that in Table 1, the "front surface" corresponds to the left surface of the corresponding lens or lens group in Figure 1 , and the "rear surface" corresponds to the right surface of the corresponding lens or lens group in Figure 1 ;

[0090] In this example, in this example, the focal length of the optical system f is 35mm, the maximum aperture is F2.8, the focal length of the first lens group S1 is fS1 = 50.30 mm, focal length f of the second lens group S2 S2 = 43.21 mm, focal length f of the third lens group S3 S3 = 59.67 mm, distance L from the vertex of the front surface of the first lens G1 to the vertex of the rear surface of the ninth lens G9 = 44.9 mm, optical back focal length BFL = 12.80 mm, half image height y' = 9.65 mm, focal length f of the first cemented lens group U1 U1 = 74.20 mm, focal length f of the second cemented lens group U2 U2 = 239.90 mm, focal length f of the third cemented lens group U3 U3 = -203.2 mm, focal length f of the eighth lens G8 G8 = 46.40 mm, air interval DS ∈ (2.00, 15.00) mm

[0091] Substituting the above values into the above relations, we get respectively:

[0092] |f S1 / f| = 1.44, |f S2 / f| = 1.23, |f S3 / f| = 1.70, |L / f| = 1.28, |BFL / f| = 0.37, |y' / f| = 0.28, |f U1 / f| = 2.12, |f U2 / f| = 6.85, |f U3 / f| = 5.81, |f G8 / f| = 1.33, 0.06 < |DS / f| < 0.43.

[0093] The above values satisfy the above relations, i.e.:

[0094] 1.10 < |f S1 / f| < 1.90; 1.00 < |f S2 / f| < 1.60; 1.40 < |f S3 / f| < 2.00;

[0095] |L / f| > 1.05; |BFL / f| < 0.55; |y' / f| < 0.40;

[0096] 1.80 < |f U1 / f| < 2.50; 3.50 < |f U2 / f| < 9.50;

[0097] 2.50 < |f U3 / f| < 6.50; 1.00 < |f G8 / f| < 1.60; |DS / f| < 0.55

[0098] Please continue to refer to Figure 2 , Figure 2 is an optical distortion curve of an optical system of a large target surface high-resolution industrial lens provided by the embodiment of the present application; as shown in the figure, the maximum optical distortion of the optical system in the full field of view range is less than 0.14%. Figure 2

[0099] The embodiment has the advantages of low distortion performance and wide working distance. Embodiment two

[0100] The embodiment provides a large target surface high-resolution industrial lens, which comprises a focusing structure and an optical system of a large target surface high-resolution industrial lens as described in embodiment one.

[0101] The focusing structure is used to drive the front group S1, the middle group S2, the diaphragm A0 and the rear group S3 as a whole to approach or move away from the image plane along the predetermined optical axis to realize focusing.

[0102] Based on the detailed description of the optical system in embodiment one, the detailed description is not repeated in this embodiment.

[0103] In summary, the embodiment realizes the optical system of a low-distortion optical lens with a focal length of 35mm, an image-side F number of 2.8, a maximum imaging surface of φ19.3mm, a highest resolution of 185lp / mm, a matching 2.74μm pixel chip, a corresponding maximum chip size of 25 million pixels, and a maximum optical distortion of less than 0.14% in the full field of view. In addition, the optical system adopts a floating focusing mode, and the light aperture can be flexibly adjusted.

[0104] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some 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 application.​

Claims

1. An optical system of a large-surface, high-resolution industrial lens, characterized in that: The invention comprises a first lens group (S1) having positive focal power, an aperture (A0), a second lens group (S2) having positive focal power, and a third lens group (S3) having 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 a predetermined optical axis; The first lens group (S1) is composed of a first lens (G1) with negative refractive power, a second lens (G2) with positive refractive power, a third lens (G3) with positive refractive power, and a fourth lens (G4) with negative refractive power, which are arranged in order from the object side to the image side; The second lens group (S2) consists of a fifth lens (G5) with negative refractive power, a sixth lens (G6) with positive refractive power, a seventh lens (G7) with negative refractive power, and an eighth lens (G8) with positive refractive power, which are arranged in order from the object side to the image side; The third lens group (S3) includes a ninth lens (G9) having positive refractive power; The aperture (A0) is provided between the fourth lens (G4) and the fifth lens (G5); The first lens (G1) and the second lens (G2) are cemented to form a first cemented lens group (U1) with positive focal power; the third lens (G3) and the fourth lens (G4) are cemented to form a second cemented lens group (U2) with positive focal power; the fifth lens (G5), the sixth lens (G6) and the seventh lens (G7) are cemented to form a third cemented lens group (U3) with negative focal power; The focal length f of the optical system, the focal length f of the first lens group (S1) S1 , the focal length f of the second lens group (S2) S2 and the focal length f of the third lens group (S3) S3 The following relationships are satisfied respectively: 1.10<|f S1 / f|<1.90; 1.00<|f S2 / f|<1.60; 1.40<|f S3 / f|<2.00。 2. The optical system of a large-surface, high-resolution industrial lens according to claim 1, characterized in that: The relative positions of the first lens group (S1) and the aperture (A0) remain unchanged, the relative positions of the aperture (A0) and the second lens group (S2) remain unchanged, and the relative positions of the third lens group (S3) and the image plane of the optical system remain 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 satisfies the relationship: |DS / f|<0.

55.

3. The optical system of a large-surface, high-resolution industrial lens according to claim 1, characterized in that: The first lens (G1), the second lens (G2), the third lens (G3), the fourth lens (G4), the fifth lens (G5), the sixth lens (G6) and the seventh lens (G7) are all meniscus lenses; the eighth lens (G8) and the ninth lens (G9) are biconvex lenses.

4. The optical system of a large-surface, high-resolution industrial lens according to claim 3, characterized in that: The focal length of the first cemented lens group (U1) is f U1 , and the ratio of the focal length f of the optical system, satisfy the relationship: 1.80<|f U1 / f|<2.50; The focal length of the second cemented lens group (U2) is f U2 , and the ratio of the focal length f of the optical system, satisfy the relationship: 3.50<|f U2 / f|<9.50; The focal length of the third cemented lens group (U3) is f U3 , and the ratio of the focal length f of the optical system, satisfy the relationship: 2.50<|f U3 / f|<6.50; The focal length of the eighth lens (G8) is f G8 , and the ratio of the focal length f of the optical system, satisfying the relationship: 1.00<|f G8 / f|<1.

60.

5. The optical system of a large-area, high-resolution industrial lens according to claim 4, characterized in that: The distance L between the front surface vertex of the first lens (G1) and the back surface vertex of the ninth lens (G9) and the focal length f of the optical system satisfy the relationship: |L / f|>1.

05.

6. The optical system of a large-area, high-resolution 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.

55.

7. The optical system of a large-area, high-resolution 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.

40.

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

9. A large-area, high-resolution industrial lens, characterized in that: An optical system comprising a focusing structure and a large-surface, high-resolution industrial lens according to 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 away from the third lens group (S3) along a predetermined optical axis.

Images