A high-resolution industrial lens

Abstract

The present invention belongs to the field of lens technology, and specifically relates to a high-resolution industrial lens, comprising a mechanical device and an optical module installed inside the mechanical device, wherein the optical module is provided with a first lens group S1, a second lens group S2, an aperture and a third lens group S3 in sequence from the object side to the image side, and the focal length of the optical module 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 , 2.5<|f s1 / f|<3.5;2.0<|f s2 / f|<3.0;0.5<|f s3 / f|<1.0. The present invention realizes an optical module of a high-resolution industrial lens with a focal length of 16mm, an image side F number of 2.8, a maximum imaging surface of φ9mm, a maximum resolution of 230lp / mm, and a maximum optical distortion of the entire field of view of less than 0.25%.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial lenses, and in particular relates to a high-resolution industrial lens. Background Art

[0002] Driven by Industry 4.0, industrial lenses are also developing and improving. However, as application demands continue to increase, the requirements for industrial lenses are also getting higher and higher. Especially in some applications such as touch screen circuit positioning monitoring, glass scratch detection, food color sorting, etc., the requirements for optical distortion and resolution of industrial lenses are getting higher and higher; at the same time, the pixels of camera chips matched with lenses tend to be miniaturized, and small pixel high-pixel chips continue to emerge.

[0003] At present, the machine vision lenses on the market, such as the patent with the patent number "201611170973.5", have a resolution of 150lp / mm and 5 million pixels, which cannot meet the demand for higher resolution; another example is the patent with the patent number "201711003199.3", which has a pixel of more than 10 million, but the distortion is only <0.5%, which also cannot meet the existing demand; another example is the patent with the patent number "201721339764.9", which also has a resolution of 150lp / mm.

[0004] In addition, the existing industrial lenses in China are generally designed for large-pixel chips, and there are few industrial lenses with small target areas and high pixels. Therefore, the research and development of industrial lenses with small pixels, high pixels and low distortion is more urgent. Summary of the invention

[0005] The purpose of the present invention is to develop an industrial lens with higher resolution to address the deficiencies of the prior art, with the highest resolution reaching 230lp / mm, which can match a 2.2μm pixel chip; a high-resolution industrial lens optical module with low distortion and good chromatic aberration correction capability.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-resolution industrial lens, comprising a mechanical device and an optical module installed inside the mechanical device, wherein the optical module is provided with a first lens group S1, a second lens group S2, an aperture and a third lens group S3 in sequence from the object side to the image side;

[0008] The first lens group S1 includes a first lens G1 with negative optical power and a meniscus structure, and a second lens G2 with positive optical power and a biconvex structure;

[0009] The second lens group S2 includes a third lens G3 with positive optical power and a meniscus structure, and a fourth lens G4 with negative optical power and a meniscus structure;

[0010] The third lens group S3 includes a fifth lens G5 with negative power and a biconcave structure, a sixth lens G6 with positive power and a biconvex structure, a seventh lens G7 with positive power and a meniscus structure, and an eighth lens G8 with positive power and a meniscus structure.

[0011] The third lens G3 and the fourth lens G4 are cemented together to form a first cemented lens group U1 with negative power, and the fifth lens G5 and the sixth lens G6 are cemented together to form a second cemented lens group U2 with positive power;

[0012] The focal length of the optical module 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 The ratio of f satisfies the relationship: 2.5<|f s1 / f|<3.5;f s2 The ratio of f satisfies the relationship: 2.0<|f s2 / f|<3.0;f s3 The ratio of f satisfies the relationship: 0.5<|f s3 / f|<1.0;.

[0013] As an improvement of the high-resolution industrial lens described in the present invention, the distance L between the vertex of the first lens G1 close to the object surface to the vertex of the eighth lens G8 close to the image surface and the focal length f of the optical module satisfy the relationship: 1.2<|L / f|.

[0014] As an improvement of the high-resolution industrial lens of the present invention, the distance from the eighth lens G8 of the optical module to the image plane, ie, the optical back focus BFL, and the focal length f of the optical module satisfy the relationship: |BFL / f|<1.2.

[0015] As an improvement of the high-resolution industrial lens of the present invention, the half-image height y' of the optical module and the focal length f of the optical module satisfy the relationship: |y' / f|<0.30.

[0016] As an improvement of the high-resolution industrial lens of the present invention, the refractive index of the first lens G1 is n1, 1.85<n1<1.95, and the refractive index of the second lens G2 is n2, 1.75<n2<1.90. The first lens group S1 has a positive and negative optical power separation structure, which can effectively reduce the influence of field curvature on image quality.

[0017] As an improvement of the high-resolution industrial lens of the present invention, the focal length of the third lens G3 is fG3 , the focal length of the fourth lens G4 is f G4 , f G3 and f s2 The ratio satisfies the relationship: 0.6<|f G3 / f s2 |<0.90,f G4 and f s2 The ratio satisfies the relationship: 0.20<|f G4 / f s2 |<0.45.

[0018] As an improvement of the high-resolution industrial lens of the present invention, the focal length of the second cemented lens group U2 is f u2 , f u2 and f s3 The ratio satisfies the relationship: 27.0<|f u2 / f s3 |<30.0, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, 1.75<n5<1.85, 1.40<n6<1.55.

[0019] As an improvement of the high-resolution industrial lens of the present invention, the refractive index of the seventh lens G7 is n7, the refractive index of the eighth lens G8 is n8, and 1.65<n7, n8<1.80.

[0020] As an improvement of the high-resolution industrial lens described in the present invention, each of the lenses is a spherical lens.

[0021] As an improvement of the high-resolution industrial lens of the present invention, the aperture of the diaphragm is a circular hole, and the aperture of the diaphragm is adjustable within the range of F2.8 to F16.

[0022] The beneficial effects of the present invention are as follows: the optical module of a high-resolution industrial lens with a focal length of 16 mm is realized through the above structure, the image side F number is 2.8, the maximum imaging surface is φ9 mm, the highest resolution can reach 230lp / mm, and it can match a 2.2μm pixel chip. When the corresponding 1 / 1.8″ chip is used, the maximum optical distortion of the full field of view is less than 0.25%; the whole group focusing method is adopted, and the light aperture can also be flexibly adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 It is a diagram of a lens optical module of an embodiment;

[0025] Figure 2 is an optical distortion curve diagram of the lens optical module of an embodiment;

[0026] In the figure: 1-aperture; 2-image plane; G1-first lens; G2-second lens; G3-third lens; G4-fourth lens; G5-fifth lens; G6-sixth lens; G7-seventh lens; G8-eighth lens; U1-first cemented lens group; U2-second cemented lens group, S1-first lens group, S2-second lens group, S3-third lens group. DETAILED DESCRIPTION

[0027] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect.

[0028] In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings, but this is not intended to limit the present invention.

[0031] Example

[0032] like Figure 1As shown, this embodiment provides a high-resolution industrial lens, including a mechanical device and an optical module installed inside the mechanical device, wherein the optical module is provided with a first lens group S1, a second lens group S2, an aperture 1 and a third lens group S3 in sequence from the object side to the image side;

[0033] The first lens group S1 includes a first lens G1 with negative power and a meniscus structure, and a second lens G2 with positive power and a biconvex structure;

[0034] The second lens group S2 includes a third lens G3 with positive power and a meniscus structure, and a fourth lens G4 with negative power and a meniscus structure;

[0035] The third lens group S3 includes a fifth lens G5 with negative power and a biconcave structure, a sixth lens G6 with positive power and a biconvex structure, a seventh lens G7 with positive power and a meniscus structure, and an eighth lens G8 with positive power and a meniscus structure;

[0036] The third lens G3 and the fourth lens G4 are cemented together to form a first cemented lens group U1 with negative power, and the fifth lens G5 and the sixth lens G6 are cemented together to form a second cemented lens group U2 with positive power;

[0037] The focal length of the optical module 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 The ratio of f satisfies the relationship: 2.5<|f s1 / f|<3.5;f s2 The ratio of f satisfies the relationship: 2.0<|f s2 / f|<3.0;f s3 The ratio of f satisfies the relationship: 0.5<|f s3 / f|<1.0;.

[0038] Furthermore, the distance L between the vertex of the first lens G1 close to the object-side surface and the vertex of the eighth lens G8 close to the image-side surface and the focal length f of the optical module satisfy the relationship: 1.2<|L / f|.

[0039] Furthermore, the distance from the eighth lens G8 of the optical module to the image plane 2, ie, the optical back focus BFL, and the focal length f of the optical module satisfy the relationship: |BFL / f|<1.2.

[0040] Furthermore, the half image height y' of the optical module and the focal length f of the optical module satisfy the relationship: |y' / f|<0.30.

[0041] Furthermore, the refractive index of the first lens G1 is n1, 1.85<n1<1.95; the refractive index of the second lens G2 is n2, 1.75<n2<1.90. The first lens group S1 has a positive and negative power separation structure, which can effectively reduce the influence of field curvature on image quality.

[0042] Furthermore, the focal length of the third lens G3 is f G3 , the focal length of the fourth lens G4 is f G4 , f G3 and f s2 The ratio satisfies the relationship: 0.6<|f G3 / f s2 |<0.90,f G4 and f s2 The ratio satisfies the relationship: 0.20<|f G4 / f s2 |<0.45.

[0043] Furthermore, the focal length of the second cemented lens group U2 is f u2 , f u2 and f s3 The ratio satisfies the relationship: 27.0<|f u2 / f s3 |<30.0, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, 1.75<n5<1.85, 1.40<n6<1.55.

[0044] Furthermore, the refractive index of the seventh lens G7 is n7, the refractive index of the eighth lens G8 is n8, and 1.65<n7, n8<1.80.

[0045] Furthermore, each lens is a spherical mirror.

[0046] Furthermore, the aperture of the diaphragm 1 is a circular hole, and the aperture of the diaphragm 1 is adjustable within the range of F2.8 to F16.

[0047] The specific optical module data are as follows:

[0048]

[0049]

[0050] In this embodiment, the focal length f of the optical module is 16 mm, and the maximum aperture is F#=2.8.

[0051] The focal length f of the first lens group S1 S1 =48.2mm, the focal length of the second lens group S2 is f S2 =-36.3mm, the focal length of the third lens group S3 is f S3=11.7mm, the distance L from the front surface vertex of the first lens G1 to the back surface vertex of the eighth lens G8 =34.8mm, the optical back focus BFL =13.5mm, the half image height y' =4.5mm, the focal length f of the third lens G3 G3 =27.4mm, the focal length of the fourth lens G4 is f G4 =-12.1mm, the focal length of the second cemented lens group is f U2 =339.8mm.

[0052] Each relation: |f S1 / f|=3.01;|f S2 / f|=2.26;|f S3 / f|=0.73;

[0053] |L / f|=2.17; |BFL / f|=0.84; |y' / f|=0.28; |f G3 / f S2 |=0.75;

[0054] |f G4 / f S2 |=0.33;|f U2 / f S3 |=29.04.

[0055] Satisfies the relationship:

[0056] 2.5<|f S1 / f|<3.5; 2.0<|f S2 / f|<3.0; 0.5<|f S3 / f|<1.0;

[0057] |L / f|>1.2; |BFL / f|<1.2; |y' / f|<0.35; 0.6<|f G3 / f S2 |<0.90;

[0058] 0.20<|f G4 / f S2 |<0.45;27.0<|f U2 / f S3 |<30.0.

[0059] Figure 2 The optical distortion curve of this embodiment is shown, and the maximum optical distortion in the whole field of view is less than 0.25%;

[0060] The above structure realizes an optical module of a high-resolution industrial lens with a focal length of 16mm, an image side F number of 2.8, a maximum imaging surface of φ9mm, a maximum resolution of 230lp / mm, and can match a 2.2μm pixel chip. When the corresponding 1 / 1.8″ chip is used, its pixels can reach 5 million pixels, and the maximum optical distortion of the full field of view is less than 0.25%. The whole-group focusing method is adopted, and its aperture can also be flexibly adjusted.

[0061] The above description shows and describes several preferred embodiments of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not depart from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A high-resolution industrial lens, characterized by: It comprises a mechanical device and an optical module installed inside the mechanical device, wherein the optical module is provided with a first lens group S1, a second lens group S2, an aperture (1) and a third lens group S3 in sequence from the object side to the image side; The first lens group S1 includes a first lens G1 with negative optical power and a meniscus structure, and a second lens G2 with positive optical power and a biconvex structure; The second lens group S2 includes a third lens G3 with positive optical power and a meniscus structure, and a fourth lens G4 with negative optical power and a meniscus structure; The third lens group S3 includes a fifth lens G5 with negative power and a biconcave structure, a sixth lens G6 with positive power and a biconvex structure, a seventh lens G7 with positive power and a meniscus structure, and an eighth lens G8 with positive power and a meniscus structure. The third lens G3 and the fourth lens G4 are cemented together to form a first cemented lens group U1 with negative power, and the fifth lens G5 and the sixth lens G6 are cemented together to form a second cemented lens group U2 with positive power; The focal length of the optical module 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 The ratio of f satisfies the relationship: 2.5<|f s1 / f|<3.5;f s2 The ratio of f satisfies the relationship: 2.0<|f s2 / f|<3.0;f s3 The ratio of f satisfies the relationship: 0.5<|f s3 / f|<1.0; The distance L between the vertex of the first lens G1 close to the object-side surface and the vertex of the eighth lens G8 close to the image-side surface and the focal length f of the optical module satisfy the relationship: 1.2<|L / f|; The distance between the eighth lens G8 of the optical module and the image plane (2), i.e., the optical back focus BFL, and the focal length f of the optical module satisfy the relationship: |BFL / f|<1.2; The half image height y' of the optical module and the focal length f of the optical module satisfy the relationship: |y' / f|<0.30; The focal length of the third lens G3 is f G3 , the focal length of the fourth lens G4 is f G4 , f G3 and f s2 The ratio satisfies the relationship: 0.6<|f G3 / f s2 |<0.90,f G4 and f s2 The ratio satisfies the relationship: 0.20<|f G4 / f s2 |<0.

45.

2. The high-resolution industrial lens according to claim 1, characterized in that: The refractive index of the first lens G1 is n1, 1.85<n1<1.95; the refractive index of the second lens G2 is n2, 1.75<n2<1.

90.

3. The high-resolution industrial lens according to claim 1, characterized in that: The focal length of the second cemented lens group U2 is f u2 , f u2 and f s3 The ratio satisfies the relationship: 27.0<|f u2 / f s3 |<30.0, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, 1.75<n5<1.85, 1.40<n6<1.

55.

4. The high-resolution industrial lens according to claim 1, characterized in that: The refractive index of the seventh lens G7 is n7, the refractive index of the eighth lens G8 is n8, and 1.65<n7, n8<1.

80.

5. The high-resolution industrial lens according to claim 1, characterized in that: Each of the lenses is a spherical mirror.

6. The high-resolution industrial lens according to claim 1, characterized in that: The aperture of the diaphragm (1) is a circular hole, and the aperture of the diaphragm (1) is adjustable within the range of F2.8 to F16.

Images