Low-distortion anti-shake lens and optical system thereof

Abstract

The application relates to the technical field of machine vision lenses, and discloses a low-distortion anti-seismic lens and an optical system thereof. The optical system is composed of a front group S1 with negative optical power, a middle group S2 with positive optical power, an aperture A0 and a rear group S3 with positive optical power which are sequentially arranged from an object side to an image side, and the positions of the front group S1, the middle group S2, the aperture A0 and the rear group S3 are relatively fixed; the focal length f of the optical system, the focal length f S1 of the front group S1, the focal length f S2 of the middle group S2 and the focal length f S3 of the rear group S3 respectively satisfy the following relations: 2.00<|f S1 / f|<3.00, 1.90<|f S2 / f|<2.50, 0.75<|f S3 / f|<1.30. The application realizes a low-distortion anti-seismic lens with a focal length of 16 mm, and the resolution can reach 185 lp / mm, and the maximum optical distortion of the full field of view is lower than 0.12%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machine vision lens, in particular to a low-distortion anti-shock lens and an optical system thereof. BACKGROUND

[0002] The imaging quality of the lens directly affects the picture effect of shooting, and the lens distortion is a key point affecting the imaging quality of the lens. The lens distortion mainly refers to that the lens cannot accurately transmit the shooting scene to the sensor, resulting in unnatural distortion of the geometric shape in the picture. With the advent of Industry 4.0 and the popularization of intelligent manufacturing, the demand for low-distortion lenses is also increasing. Some automatic industries have very high requirements for shooting quality, such as automatic assembly, mechanical arm, high-speed reciprocating motion production line, etc. Since the equipment is running at high speed all the time, the lens is required to still obtain clear and high-resolution images in a vibrating environment, so the lens has high distortion requirements and good anti-shock performance.

[0003] At present, the existing anti-shock lenses in China have different degrees of deficiencies in resolution and distortion performance, and the specifications are not perfect. Especially in the semiconductor and electronic industries, for example, in the process of semiconductor manufacturing and electronic assembly, the anti-shock lens is used for precise detection or measurement, which requires the distortion of the anti-shock lens to be as low as possible. Therefore, the research and development of low-distortion anti-shock lenses are more urgent.

[0004] The above information is given as background information only to assist with an understanding of the present disclosure, and should not be taken as an acknowledgement or admission that any of the above information forms part of the prior art with respect to the present disclosure. SUMMARY

[0005] The purpose of the present application is to provide a low-distortion anti-shock 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 low-distortion anti-shock lens, which is composed of a front group S1 with negative focal power, a middle group S2 with positive focal power, an aperture A0 and a rear group S3 with positive focal power arranged in order from the object side to the image side, and the positions of the front group S1, the middle group S2, the aperture A0 and the rear group S3 are relatively fixed; the front group S1, the middle group S2 and the rear 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 front group S1, the focal length f S2 of the middle group S2 and the focal length f S3respectively satisfy the following relationships:

[0009] 2.00<|f S1 1.90<|f S2 0.75<|f S3 1.30.

[0010] Optionally, the front group S1 is composed of a first lens G1 with negative optical power;

[0011] The middle group S2 is composed of a second lens G2 with positive optical power, a third lens G3 with negative optical power, a fourth lens G4 with positive optical power, and a fifth lens G5 with negative optical power;

[0012] The rear group S3 is composed of a sixth lens G6 with positive optical power, a seventh lens G7 with negative optical power, an eighth lens G8 with positive optical power, and a ninth lens G9 with positive optical power;

[0013] Wherein, the first lens G1, the third lens G3, the fourth lens G4, the fifth lens G5 and the eighth lens G8 are meniscus lenses, the second lens G2 is a double convex lens, the sixth lens G6 is a plano-convex lens or a double convex lens, the seventh lens G7 is a double concave lens, and the ninth lens G9 is a double convex lens or a meniscus lens.

[0014] Optionally, the second lens G2 and the third lens G3 are cemented into a first cemented lens group U1 with positive optical power; the fourth lens G4 and the fifth lens G5 are cemented into a second cemented lens group U2 with negative optical power; the sixth lens G6 and the seventh lens G7 are cemented into a third cemented lens group U3 with negative optical power;

[0015] The focal length of the first cemented lens group U1 is f U1 , the ratio of f U1 and the focal length f of the optical system satisfies the relationship: 1.20<|f U1 / f|<2.00; the focal length of the second cemented lens group is f U2 , the ratio of f U2 and f satisfies the relationship: 1.90<|f U2 / f|<3.00; the focal length of the third cemented lens group is f U3 , the ratio of f U3 and f satisfies the relationship: 3.00<|f U3 / f|<4.50.

[0016] Optionally, the distance L between the front surface vertex of the first lens G1 and the rear surface vertex of the ninth lens G9 satisfies the relationship:

[0017] |L / f|>2.90;

[0018] The front surface of the first lens G1 is a side surface of the first lens G1 facing away from the second lens G2, and the back surface of the ninth lens G9 is a side surface of the ninth lens G9 facing away from the eighth lens G8; the vertex of the front surface of the first lens G1 and the vertex of the back surface of the ninth lens G9 are both on the predetermined optical axis.

[0019] Optionally, the ratio of the back focal length BFL of the optical system to f satisfies the relationship: |BFL / f|<1.20.

[0020] Optionally, the ratio of the half image height y' of the optical system to f satisfies the relationship: |y' / f|<0.50.

[0021] Optionally, the focal length of the eighth lens G8 is f G8 , and the ratio of f G8 to f satisfies the relationship: 1.40<|f G8 / f|<2.50.

[0022] The focal length of the ninth lens G9 is f G9 , and the ratio of f G9 to f satisfies the relationship: 0.85<|f G9 / f|<1.60.

[0023] Optionally, when the object distance changes, all the spherical lenses move together as a whole, and focusing is achieved by changing the back focal length BFL of the optical system, which ensures structural stability and achieves anti-shock effect.

[0024] Optionally, the aperture of the diaphragm A0 is a circular hole, and the center of the circular hole is on the predetermined optical axis.

[0025] The aperture value of the diaphragm ranges from F2.8 to F16.

[0026] In a second aspect, the application provides a low-distortion anti-shock lens, which comprises a focusing structure and an optical system of a low-distortion anti-shock lens as described above.

[0027] The focusing structure can drive the front group S1, the middle group S2, the diaphragm A0 and the rear group S3 to move together along the predetermined optical axis to approach or move away from the image plane, so as to achieve focusing.

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

[0029] The optical system provided by the application adopts the whole-group focusing mode, realizes a low-distortion anti-shock lens with a focal length of 16mm, an image F number of 2.8, and a maximum imaging surface of The resolution thereof can reach 185 lp / mm, that is, when corresponding to the maximum imaging chip, the pixels thereof can reach 79 million, and the maximum optical distortion of the full field of view is less than 0.12%.

[0030] The present application has other characteristics and advantages, which will be apparent from and / or set forth in the accompanying drawings and the following detailed description, which together serve to explain certain principles of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the 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 without creative labor on the basis of these drawings.

[0032] Figure 1 is a structural schematic diagram of an optical system of a low-distortion anti-shock lens provided by an embodiment of the present application.

[0033] Figure 2 is an optical distortion curve of an optical system of a low-distortion anti-shock lens provided by an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the 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 without creative labor on the basis of these drawings.

[0035] In this document, the term "embodiment" means that the specific feature, structure or characteristic described in connection with the embodiment can 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, 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.

[0036] Unless otherwise defined, the meanings of the technical terms used herein are the same as those commonly understood by those skilled in the art to which the present application belongs; the use of related terms in this document is only for the purpose of describing specific embodiments, and is not intended to limit the present application.

[0037] 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 an "or" logical relationship.

[0038] In the present application, the 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 and secondary, or order relationship between the entities or operations.

[0039] In the present application, without more limitation, the "includes", "contains", "has" 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 the elements inherent in such process, method or product.

[0040] As the same understanding as 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.

[0041] In the description of the embodiments of the present application, the spatial-related expressions used, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "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 do not 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.

[0042] Unless otherwise clearly indicated or implied to the contrary by context, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of stated integers or steps but not the exclusion of any other integers or steps. Unless otherwise indicated or implied by context, the word "connected" is intended to include where appropriate "directly connected" as well as "indirectly connected" and "functionally connected".

[0043] Embodiment One:

[0044] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of an optical system of a low-distortion anti-shake lens provided by an embodiment of the present application.

[0045] As shown in Figure 1 , the optical system comprises, arranged in order from the object side to the image side, a front group S1 having negative optical power, a middle group S2 having positive optical power, a stop A0, and a rear group S3 having positive optical power, and the positions of the front group S1, the middle group S2, the stop A0, and the rear group S3 are relatively fixed; the front group S1, the middle group S2, and the rear 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;

[0046] The focal length f of the optical system, the focal length f S1 of the front group S1, the focal length f S2 of the middle group S2, and the focal length f S3 of the rear group S3 respectively satisfy the following relationships:

[0047] 2.00<|f S1 / f|<3.00; 1.90<|f S2 / f|<2.50; 0.75<|f S3 / f|<1.30.

[0048] Illustratively, as an optional implementation, the front group S1 comprises a first lens G1 having negative optical power.

[0049] The middle group S2 comprises a second lens G2 having positive optical power, a third lens G3 having negative optical power, a fourth lens G4 having positive optical power, and a fifth lens G5 having negative optical power;

[0050] The rear group S3 comprises a sixth lens G6 having positive optical power, a seventh lens G7 having negative optical power, an eighth lens G8 having positive optical power, and a ninth lens G9 having positive optical power;

[0051] Wherein, the first lens G1, the third lens G3, the fourth lens G4, the fifth lens G5 and the eighth lens G8 are meniscus lenses, the second lens G2 is a double convex lens, the sixth lens G6 is a plano-convex lens or a double convex lens, the seventh lens G7 is a double concave lens, and the ninth lens G9 is a double convex lens or a meniscus lens.

[0052] Further, the second lens G2 and the third lens G3 are cemented into a first cemented lens group U1 with positive focal power; the fourth lens G4 and the fifth lens G5 are cemented into a second cemented lens group U2 with negative focal power; the sixth lens G6 and the seventh lens G7 are cemented into a third cemented lens group U3 with negative focal power;

[0053] The focal length of the first cemented lens group U1 is f U1 , the ratio of f U1 and the focal length f of the optical system satisfies the relationship: 1.20<|f U1 / f|<2.00; the focal length of the second cemented lens group is f U2 , the ratio of f U2 and f satisfies the relationship: 1.90<|f U2 / f|<3.00; the focal length of the third cemented lens group is f U3 , the ratio of f U3 and f satisfies the relationship: 3.00<|f U3 / f|<4.50.

[0054] Specifically, the distance L between the vertex of the front surface of the first lens G1 and the vertex of the back surface of the ninth lens G9 satisfies the relationship:

[0055] |L / f|>2.90;

[0056] Wherein, the front surface of the first lens G1 is the side surface of the first lens G1 away from the second lens G2, and the back surface of the ninth lens G9 is the side surface of the ninth lens G9 away from the eighth lens G8; the vertex of the front surface of the first lens G1 and the vertex of the back surface of the ninth lens G9 are both on the predetermined optical axis.

[0057] Further, the focal length of the eighth lens G8 is f G8 , the ratio of f G8 and f satisfies the relationship: 1.40<|f G8 / f|<2.50;

[0058] The focal length of the ninth lens G9 is f G9 , the ratio of f G9 and f satisfies the relationship: 0.85<|f G9 / f|<1.60.

[0059] In this embodiment, the ratio of the optical back focal length BFL of the optical system to f satisfies the relationship: |BFL / f|<1.20.

[0060] In this embodiment, the ratio of the half image height y' of the optical system to f satisfies the relationship: |y' / f|<0.50.

[0061] It should be noted that in this embodiment, when the object distance changes, all the spherical lenses move together, that is, the focusing is performed by changing the optical back focal length BFL of the optical system.

[0062] Further, the aperture of the diaphragm A0 is a circular hole, and the center of the circular hole is on the predetermined optical axis.

[0063] The aperture value of the diaphragm A0 is in the range of F2.8 to F16. It can be understood that the aperture value of the diaphragm A0 needs to be adjusted according to the specific application scenario.

[0064] For example, in this example, the related data of the optical system is shown in Table 1:

[0065] Table 1

[0066]

[0067]

[0068] It should be noted that in Table 1, the "front surface" corresponds to the left surface of the lens or lens group in Figure 1 , and the "rear surface" corresponds to the right surface of the lens or lens group in Figure 1 ; or it can be understood that: the object side is on the left side, the image side (or image surface) is on the right side, the surface close to the object side is the "front surface", and the surface close to the image side is the "rear surface". Figure 1 Figure 1

[0069] In this example, the focal length f of the optical system is 16 mm, the maximum aperture is F2.8, the focal length f of the front group S1 is S1 =-40.40 mm, the focal length f of the middle group S2 is S2 =36.00 mm, the focal length f of the rear group S3 is S3 =14.60 mm, the distance L from the front surface vertex of the first lens G1 to the rear surface vertex of the ninth lens G9 is 53.70 mm, the optical back focal length BFL is 13.90 mm, the half image height y' is 5.5 mm, the focal length f of the first cemented lens group U1 is U1 =25.60 mm, the focal length f of the second cemented lens group U2 is U2 =-35.60 mm, and the focal length f of the third cemented lens group U3 is​​U3 = -58.40 mm, focal length f of the eighth lens G8 G8 = 31.00 mm, focal length f of the ninth lens G9 G9 = 20.90 mm.

[0070] Substituting the above values into each of the relational expressions, the following are obtained, respectively:

[0071] |f S1 / f| = 2.53, |f S2 / f| = 2.25, |f S3 / f| = 0.91, |L / f| = 3.36, |BFL / f| = 0.87, |y' / f| = 0.34, |f U1 / f| = 1.60,

[0072] |f U2 / f| = 2.23; |f U3 / f| = 3.65; |f G8 / f| = 1.94; |f G9 / f| = 1.31.

[0073] Therefore, the relational expressions of the present embodiment are satisfied, i.e.:

[0074] 2.00<|f S1 / f| < 3.00; 1.90<|f S2 / f| < 2.50; 0.75<|f S3 / f| < 1.30;

[0075] |L / f| > 2.90; |BFL / f| < 1.20; |y' / f| < 0.50;

[0076] 1.20<|f U1 / f| < 2.00; 1.90<|f U2 / f| < 3.00;

[0077] 3.00<|f U3 / f| < 4.50; 1.40<|f G8 / f| < 2.50;

[0078] 0.85<|f G9 / f| < 1.60.

[0079] Please continue to refer to Figure 2 , Figure 2 is an optical distortion curve of an optical system of a low-distortion anti-shake lens provided by the present embodiment; as shown in Figure 2 , according to experimental verification, the maximum optical distortion of the optical system in the full field of view range is lower than 0.12%.

[0080] The embodiment realizes a low-distortion anti-vibration lens with a focal length of 16 mm by the structural design of the optical system, and the maximum optical distortion of the full field of view is less than 0.12%; and the embodiment adopts the whole-group focusing mode, which ensures the structural stability and realizes the anti-vibration effect; in addition, the light aperture can be flexibly adjusted, and can be applied to various application scenarios.

[0081] Embodiment two:

[0082] The embodiment provides a low-distortion anti-vibration lens, comprising a focusing structure and an optical system of a low-distortion anti-vibration lens as described in embodiment one.

[0083] The focusing structure is used to drive the front group S1, the middle group S2, the diaphragm A0 and the rear group S3 to move together along the predetermined optical axis to realize focusing.

[0084] Based on the detailed description of the optical system in embodiment one, the detailed description is not repeated in this embodiment.

[0085] In summary, the embodiment realizes a low-distortion anti-vibration lens with a focal length of 16 mm, an image-side F number of 2.8, and a maximum imaging surface of The resolution can reach 185 lp / mm, that is, the corresponding maximum imaging chip has a pixel of 7.9 million, the maximum optical distortion of the full field of view is less than 0.12%, and the lens has high resolution and low distortion, and good anti-vibration performance, which meets the application requirements of precise detection or measurement.

[0086] 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 the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements do not make 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 for a low-distortion, anti-shake lens, characterized in that, The system consists of a front group S1 with negative optical power, a middle group S2 with positive optical power, an aperture stop A0, and a rear group S3 with positive optical power, arranged sequentially from the object side to the image side. The positions of the front group S1, the middle group S2, the aperture stop A0, and the rear group S3 are relatively fixed relative to each other. The front group S1, the middle group S2, and the rear group S3 are each composed of several spherical lenses, and the optical axes of all the spherical lenses coincide with the predetermined optical axis. The focal length f of the optical system and the focal length f of the front group S1 S1 The focal length f of the middle group S2 S2 And the focal length f of the rear group S3 S3 They respectively satisfy the following relations: 2.00<|f S1 / f|<3.00;1.90<|f S2 / f|<2.50;0.75<|f S3 / f|<1.30; The front group S1 consists of a first lens G1 with negative optical power; The middle group S2 consists of a second lens G2 with positive power, a third lens G3 with negative power, a fourth lens G4 with positive power, and a fifth lens G5 with negative power. The rear group S3 consists of a sixth lens G6 with positive optical power, a seventh lens G7 with negative optical power, an eighth lens G8 with positive optical power, and a ninth lens G9 with positive optical power. Among them, the first lens G1, the third lens G3, the fourth lens G4, the fifth lens G5 and the eighth lens G8 are meniscus lenses, the second lens G2 is a biconvex lens, the sixth lens G6 is a plano-convex lens or a biconvex lens, the seventh lens G7 is a biconcave lens, and the ninth lens G9 is a biconvex lens or a meniscus lens.

2. The optical system of a low-distortion anti-shake lens according to claim 1, characterized in that, The second lens G2 and the third lens G3 are cemented together to form a first cemented lens group U1 with positive optical power; The fourth lens G4 and the fifth lens G5 are cemented together to form a second cemented lens group U2 with negative optical power; the sixth lens G6 and the seventh lens G7 are cemented together to form a third cemented lens group U3 with negative optical power. The focal length of the first cemented lens group U1 is f U1 f U1 The ratio of the focal length f of the optical system to the focal length f of the system satisfies the following relationship: 1.20 < |f U1 / f|<2.00; the focal length of the second cemented lens group is f U2 f U2 The ratio of f to f satisfies the following relationship: 1.90 < |f| U2 / f|<3.00; the focal length of the third cemented lens group is f U3 f U3 The ratio of f to f satisfies the following relationship: 3.00 < |f| U3 / f|<4.

50.

3. The optical system of a low-distortion anti-shake lens according to claim 2, characterized in that, 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 satisfies the following relationship: |L / f|>2.90; Wherein, the front surface of the first lens G1 is the side surface of the first lens G1 that is away from the second lens G2, and the rear surface of the ninth lens G9 is the side surface of the ninth lens G9 that is away from the eighth lens G8; the vertex of the front surface of the first lens G1 and the vertex of the rear surface of the ninth lens G9 are both on the predetermined optical axis.

4. The optical system of a low-distortion anti-shake lens according to claim 2, characterized in that, The ratio of the optical back focal length BFL to f of the optical system satisfies the following relationship: |BFL / f| < 1.

20.

5. The optical system of a low-distortion anti-shake lens according to claim 2, characterized in that, The ratio of the half-image height y' to f of the optical system satisfies the relationship: |y' / f| < 0.

50.

6. The optical system of a low-distortion anti-shake lens according to claim 2, characterized in that, The focal length of the eighth lens G8 is f G8 f G8 The ratio of f to f satisfies the following relationship: 1.40 < |f| G8 / f|<2.50; The focal length of the ninth lens G9 is f G9 f G9 The ratio of f to f satisfies the following relationship: 0.85 < |f| G9 / f|<1.

60.

7. The optical system of a low-distortion anti-shake lens according to claim 4, characterized in that, When the object distance changes, all the spherical lenses move together as a whole, and focusing is achieved by changing the optical back focal length (BFL) of the optical system.

8. The optical system of a low-distortion anti-shake lens according to claim 1, characterized in that, The aperture of the stop A0 is a circular hole, and the center of the circular hole is on the predetermined optical axis; The aperture value ranges from F2.8 to F16.

9. A low-distortion, anti-shake lens, characterized in that, Includes a focusing structure and an optical system for a low-distortion, anti-shake lens as described in any one of claims 1-8; The focusing structure can drive the front group S1, the middle group S2, the aperture A0 and the rear group S3 together to move closer to or further away from the image plane along a predetermined optical axis.

Images