CN214586200U - Lens and image acquisition component for industrial machine vision - Google Patents

Abstract

The utility model provides a lens and an image acquisition component for industrial machine vision, wherein the lens for industrial machine vision comprises a reverse telephoto lens group and a rear lens group which are coaxially arranged from an object side to an image side in sequence; the anti-telephoto lens group comprises a first negative lens group and a second positive lens group which are arranged in sequence; the first negative lens group comprises at least one lens, and the second positive lens group comprises at least one lens; the rear lens group includes at least one lens. The utility model provides a camera lens for industrial machine vision through setting up anti-telephoto lens group and rear lens group, and anti-telephoto lens group is used for converging the light of penetrating into to in the light incidence to rear lens group after the convergence, can realize the low distortion under the condition of the big angle of vision of camera lens realization, thereby guarantee to be absorbed the image quality and the resolution ratio of target.

Description

Lens and image acquisition component for industrial machine vision

Technical Field

The utility model belongs to the technical field of optical device, concretely relates to camera lens and image acquisition part for industrial machine vision.

Background

With the development of computer vision technology, an image acquisition component and a robot can be combined, and the image acquisition component serves as the eyes of the robot and can assist the robot to complete work in a specific industry. Taking industries such as manufacturing and logistics as examples, the image acquisition component and the robot can be combined to complete work such as stacking, feeding, object grabbing and the like.

The image acquisition component may generally include devices such as an optical lens, an image sensor, and an image processor, and the design of the optical lens will directly affect the imaging quality, and the imaging quality will affect the working accuracy of the robot. In some application scenarios, such as an article grabbing application scenario, in a case where the article is large in size, the optical lens is required to have a large field angle to complete image acquisition.

In general, the angle of field of an optical lens can be increased by decreasing the focal length of the optical lens, but decreasing the focal length of the lens tends to increase the lens distortion, resulting in a decrease in image quality.

SUMMERY OF THE UTILITY MODEL

For overcoming the problem that exists in the correlation technique at least to a certain extent, the utility model provides a camera lens and image acquisition part for industrial machine vision.

According to a first aspect of embodiments of the present invention, the present invention provides a lens for industrial machine vision, comprising a reverse telephoto lens group and a rear lens group coaxially arranged in order from an object side to an image side;

the anti-telephoto lens group comprises a first negative lens group and a second positive lens group which are arranged in sequence; the first negative lens group comprises at least one lens, and the second positive lens group comprises at least one lens; the rear lens group includes at least one lens.

In the above-mentioned lens for industrial machine vision, still include the diaphragm, the diaphragm sets up between anti telephoto lens group and the rear lens group.

Further, the aperture of the diaphragm is: 5 mm-9 mm.

In the lens barrel for industrial machine vision, the distance between the reverse telephoto lens group and the rear lens group is 2mm to 13 mm; the distance between the first negative lens group and the second positive lens group is 0.8 mm-3 mm.

In the lens barrel for industrial machine vision, the focal length of the first negative lens group is-27 mm to-15 mm; the focal length of the second positive lens group is 6-17 mm; the focal length of the rear lens group is 6 mm-17 mm.

Further, the first negative lens group comprises a first negative lens and a second positive lens which are arranged in sequence, and the focal length of the first negative lens is-12 mm to-8 mm; the focal length of the second positive lens is 50-57 mm; the distance between the first negative lens and the second positive lens is 2 mm-6 mm.

Furthermore, the second positive lens group comprises a third negative lens and a fourth positive lens which are arranged in sequence, and the focal length of the third negative lens is-30 mm to-34 mm; the focal length of the fourth positive lens is 10-14 mm; the distance between the third negative lens and the fourth positive lens ranges from 3mm to 6 mm.

Furthermore, the rear lens group comprises a fifth positive lens and a sixth positive lens which are arranged in sequence, and the focal length of the fifth positive lens is 31-35 mm; the focal length of the sixth positive lens is 18-22 mm; and the distance between the fifth positive lens and the sixth positive lens is 2-7 mm.

Furthermore, the first negative lens and the second positive lens are spherical lenses made of optical glass, and the third negative lens, the fourth positive lens, the fifth positive lens and the sixth positive lens are aspheric lenses made of optical plastic.

According to the utility model discloses in the second aspect of the embodiment, the utility model provides an image acquisition part, it includes any one of the aforesaid a camera lens for industrial machine vision.

According to the above embodiments of the present invention, at least the following advantages are obtained: the utility model provides a camera lens for industrial machine vision through setting up anti-telephoto lens group and rear lens group, and anti-telephoto lens group is used for converging the light of penetrating into to in the light incidence to rear lens group after the convergence, can realize the low distortion under the condition of the big angle of vision of camera lens realization, thereby guarantee to be absorbed the image quality and the resolution ratio of target. In addition, the focal length and material of each lens in the anti-telephoto lens group and the rear lens group and the distance between each adjacent lens are reasonably set, so that the lens can realize a large field angle, has low distortion, and meets the requirements of a machine vision system in robots in the industries of manufacturing, logistics and the like.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification of the invention, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic structural diagram of a lens for industrial machine vision according to an embodiment of the present invention.

Fig. 2 is a second schematic structural diagram of a lens for industrial machine vision according to an embodiment of the present invention.

Fig. 3 is a diagram of an optical modulation transfer function of an optical system of a lens for industrial machine vision under normal temperature and pressure conditions according to an embodiment of the present invention.

Fig. 4 is a distortion curve diagram of a lens for industrial machine vision according to an embodiment of the present invention.

Fig. 5 is an image plane relative illuminance diagram of a lens for industrial machine vision according to an embodiment of the present invention.

Description of reference numerals:

1. a reverse telephoto lens group; 11. a first negative lens group; 111. a first negative lens; 112. a second positive lens; 12. a second positive lens group; 121. a third negative lens; 122. a fourth positive lens;

2. a rear lens group; 21. a fifth positive lens; 22. a sixth positive lens;

3. and (4) a diaphragm.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the spirit of the present invention will be described in detail with reference to the accompanying drawings, and any person skilled in the art can change or modify the techniques taught by the present invention without departing from the spirit and scope of the present invention after understanding the embodiments of the present invention.

The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention. Additionally, the same or similar numbered elements/components used in the drawings and the embodiments are used to represent the same or similar parts.

As used herein, the terms "first," "second," …, etc. do not denote any order or sequential importance, nor are they used to limit the invention, but rather are used to distinguish one element from another or from another element or operation described in the same technical language.

With respect to directional terminology used herein, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Accordingly, the directional terminology used is intended to be illustrative and is not intended to be limiting of the present teachings.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

As used herein, "and/or" includes any and all combinations of the described items.

References to "plurality" herein include "two" and "more than two"; reference to "multiple sets" herein includes "two sets" and "more than two sets".

As used herein, the terms "substantially", "about" and the like are used to modify any slight variation in quantity or error that does not alter the nature of the variation. In general, the range of slight variations or errors that such terms modify may be 20% in some embodiments, 10% in some embodiments, 5% in some embodiments, or other values. It should be understood by those skilled in the art that the aforementioned values can be adjusted according to actual needs, and are not limited thereto.

Certain words used to describe the invention are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the invention.

With the development of computer vision technology, an image acquisition component and a robot can be combined, and the image acquisition component serves as the eyes of the robot and can assist the robot to complete work in a specific industry. Taking industries such as manufacturing and logistics as examples, the image acquisition component and the robot can be combined to complete work such as stacking, feeding, object grabbing and the like.

The image acquisition component may generally include devices such as an optical lens, an image sensor, and an image processor, and the design of the optical lens will directly affect the imaging quality, and the imaging quality will affect the working accuracy of the robot. In some application scenarios, such as an article grabbing application scenario, in a case where the article is large in size, the optical lens is required to have a large field angle to complete image acquisition.

In general, the angle of field of an optical lens can be increased by decreasing the focal length of the optical lens, but decreasing the focal length of the lens tends to increase the lens distortion, resulting in a decrease in image quality.

Fig. 1 is a schematic structural diagram of a lens for industrial machine vision according to an embodiment of the present invention.

As shown in fig. 1, a lens barrel for industrial machine vision according to an embodiment of the present invention includes a telephoto lens group 1 and a rear lens group 2 coaxially arranged in order from an object side to an image side. Wherein, the distance between the reverse telephoto lens group 1 and the rear lens group 2 is 2mm to 13 mm. The focal length of the whole lens for industrial machine vision is 4.6mm, 6 mm. The field angle of the whole lens for industrial machine vision is 80-90 degrees, and the f-number is 1.7-2.5.

Wherein the reverse telephoto lens group 1 includes a first negative lens group 11 and a second positive lens group 12 which are arranged in this order. Specifically, the focal length of the first negative lens group 11 is-27 mm to-15 mm. The first negative lens group 11 includes at least one lens, and the lens may be made of optical glass material. The focal length of the second positive lens group 12 is 6mm to 17 mm. The second positive lens group 12 includes at least one lens, and the lens may be made of optical glass or optical plastic material.

The focal length of the rear lens group 2 is 6mm to 17 mm. The rear lens group 2 is a positive lens group, which includes at least one lens, and the lens can be made of optical glass or optical plastic material.

It should be noted that the lenses in the reverse telephoto lens group 1 and the rear lens group 2 may be spherical lenses or aspherical lenses.

The embodiment of the utility model provides an among the camera lens for industrial machine vision, anti-telephoto lens group 1 and rear lens group 2 all converge the light of penetrating, can realize low distortion under the condition that the camera lens realizes the big angle of vision to guarantee to be absorbed the image quality and the resolution ratio of target. Through rationally setting the focal length, the material of each lens and the distance between each adjacent lens in anti-telephoto lens group 1 and the rear lens group 2, the camera lens can meet the requirements of a machine vision system in industrial robots such as manufacturing and logistics.

Since distortion is aberration that increases with the third power of the field height, the distortion of a large field lens is generally large. The embodiment of the utility model provides an in the camera lens for industrial machine vision, through carrying out reasonable setting to the face type parameter of each lens in the camera lens, structural parameter and the interval of material and each camera lens, can effectively reduce the lens distortion, improve image quality.

In a specific embodiment, the focal length of the whole lens for industrial machine vision is 5mm to 5.99 mm. The distance between the reverse telephoto lens group 1 and the rear lens group 2 is 2mm to 5 mm.

Note that the distance between the reverse telephoto lens group 1 and the rear lens group 2 refers to a straight-line distance between an intersection point of a surface of a lens close to the rear lens group 2 in the reverse telephoto lens group 1 and the optical lens main axis and an intersection point of a surface of a lens close to the reverse telephoto lens group 1 in the rear lens group 2 and the optical lens main axis.

In a specific embodiment, the distance between the first negative lens group 11 and the second positive lens group 12 in the reverse telephoto lens group 1 is 0.8mm to 3 mm.

Note that, as shown in fig. 2, the distance between the first negative lens group 11 and the second positive lens group 12 refers to a straight-line distance between an intersection point of a surface of a lens in the first negative lens group 11 close to the second positive lens group 12 and the principal axis of the optical lens and an intersection point of a surface of a lens in the second positive lens group 12 close to the first negative lens group 11 and the principal axis of the optical lens.

In a specific embodiment, the first negative lens group 11 comprises a first negative lens 111 and a second positive lens 112 sequentially disposed, wherein the focal length of the first negative lens 111 is from-12 mm to-8 mm, and is made of lanthanum crown glass. The focal length of the second positive lens 112 is 50mm to 57mm, and the second positive lens is made of heavy flint glass or heavy barium flint glass.

The distance between the first negative lens 111 and the second positive lens 112 is 2mm to 6 mm.

As shown in fig. 2, assuming that an intersection point of the major axis of the first negative lens 111 and the surface of the first negative lens 111 close to the second positive lens 112 is point a and an intersection point of the major axis of the second positive lens 112 and the surface of the second positive lens 112 close to the first negative lens 111 is point B, the distance between the first negative lens 111 and the second positive lens 112 is the distance of the line segment AB.

In a specific embodiment, the second positive lens group 12 includes a third negative lens 121 and a fourth positive lens 122 sequentially disposed, wherein the third negative lens 121 has a focal length of-30 mm to-34 mm, and is made of optical plastic. The fourth positive lens 122 has a focal length of 10mm to 14mm and is made of optical plastic.

The distance between the third negative lens 121 and the fourth positive lens 122 ranges from 3mm to 6 mm.

As shown in fig. 2, assuming that an intersection of the major axis of the third negative lens 121 and the surface of the third negative lens 121 close to the fourth positive lens 122 is point C and an intersection of the major axis of the fourth positive lens 122 and the surface of the fourth positive lens 122 close to the third negative lens 121 is point D, the distance between the third negative lens 121 and the fourth positive lens 122 is the distance of the line segment CD.

In a specific embodiment, the rear lens group 2 includes a fifth positive lens 21 and a sixth positive lens 22, which are sequentially disposed, wherein the focal length of the fifth positive lens 21 is 31mm to 35mm, and is made of optical plastic. The focal length of the sixth positive lens 22 is 18 mm-22 mm, and the sixth positive lens is made of optical plastics.

The distance between the fifth positive lens 21 and the sixth positive lens 22 is 2mm to 7 mm.

As shown in fig. 2, assuming that an intersection of the major axis of the fifth positive lens 21 and the surface of the fifth positive lens 21 close to the sixth positive lens 22 is point E and an intersection of the major axis of the sixth positive lens 22 and the surface of the sixth positive lens 22 close to the fifth positive lens 21 is point F, the distance between the fifth positive lens 21 and the sixth positive lens 22 is the distance of the line segment EF.

In a specific embodiment, the diameter of the first negative lens 111 may be set to 15 mm. The total length of the whole lens for industrial machine vision is 35 mm-40 mm.

As an optional implementation manner of the embodiment of the utility model, the embodiment of the utility model provides a camera lens for industrial machine vision still includes diaphragm 3, and diaphragm 3 sets up between anti telephoto lens group 1 and rear lens group 2. The aperture of the diaphragm 3 is: 5 mm-9 mm. The arrangement of the diaphragm 3 can ensure that coma or astigmatism of the whole lens is minimum, and meanwhile, the whole size of the lens can be smaller.

As an optional implementation manner of the embodiment of the present invention, the first negative lens 111 and the second positive lens 112 may both adopt spherical lenses, and the third negative lens 121, the fourth positive lens 122, the fifth positive lens 21, and the sixth positive lens 22 may all adopt aspheric lenses. Because aspherical lens's curvature radius changes along with the center pin, it can be used for improving optical quality, consequently, third negative lens 121, fourth positive lens 122, fifth positive lens 21 and sixth positive lens 22 all adopt aspherical lens can reduce the utility model discloses the optical element quantity for in the camera lens of industrial machine vision that the embodiment provides can reach fine imaging quality with less lens quantity, and the quantity of lens is less light energy loss less, can reduce design cost.

Of course, according to actual needs, the first negative lens 111 may be a spherical lens, and the second positive lens 112, the third negative lens 121, the fourth positive lens 122, the fifth positive lens 21, and the sixth positive lens 22 may be aspheric lenses. Aspheric lenses may be used for the first negative lens 111, the second positive lens 112, the third negative lens 121, the fourth positive lens 122, the fifth positive lens 21, and the sixth positive lens 22.

Specifically, the first negative lens 111 and the second positive lens 112 are spherical lenses made of optical glass, and the third negative lens 121, the fourth positive lens 122, the fifth positive lens 21, and the sixth positive lens 22 are aspheric lenses made of optical plastic.

The first negative lens 111 and the second positive lens 112 are spherical lenses made of optical glass, so that the influence of the external environment temperature on the inside of the lens can be effectively reduced, and the imaging quality reduction caused by temperature deformation of each aspheric lens made of optical plastic is avoided; in addition, since the glass has a high thermal deformation temperature, when the temperature of the working environment is high, the spherical lenses made of optical glass are not easily deformed by heat for both the first negative lens 111 and the second positive lens 112.

The processing technology of the aspheric lens made of the optical plastic material is simple, and the cost is low; in addition, the density of the optical plastic material is smaller than that of the optical glass material, and the optical plastic material is favorable for reducing the weight of the lens. By providing the first negative lens 111 and the second positive lens 112 as spherical lenses made of optical glass and the third lens, the fourth lens, the fifth lens, and the sixth lens as aspherical lenses made of optical plastic, a good imaging effect can be achieved with as few lenses as possible.

As an optional implementation manner of the embodiment of the utility model, the embodiment of the utility model provides a camera lens for industrial machine vision still includes the light filter, and the light filter sets up at rear lens group 2's rear along light incident direction. When the lens for industrial machine vision is used in different application scenes, the spectral range of light passing through the optical filter can be adjusted according to needs, so that the lens for industrial machine vision can better image in a working spectrum band.

As an optional implementation manner of the embodiment of the utility model, the embodiment of the utility model provides a camera lens for industrial machine vision still includes the glass piece, and the glass piece sets up the rear at the light filter along light incident direction. The glass sheet is used to protect a sensor in a camera used in cooperation with a lens.

As an optional implementation manner of the embodiment of the present invention, by reasonably selecting each lens, and simultaneously, reasonably setting the relevant parameters of each lens, the field angle of the lens can reach 80 to 90 degrees, that is, compared with the existing lens, the lens for industrial machine vision provided by the embodiment of the present invention can realize large field monitoring; meanwhile, on the premise of a large field angle, the distortion of the full field of view is less than 0.8 percent. Therefore, the embodiment of the utility model provides a camera lens for industrial machine vision can realize the low distortion formation of image of big visual field.

By arranging the lenses in the lens barrel for industrial machine vision according to the above embodiment, schematic diagrams representing the imaging effect of the lens barrel can be obtained as shown in fig. 3, 4 and 5.

As shown in fig. 3, the Modulation Transfer Function (MTF) is a relationship between a Modulation degree and a logarithm per millimeter of a line in an image, and is used to evaluate the detail reduction capability of a scene. The modulation is the ratio of the difference between the maximum and minimum intensity and the sum of the maximum and minimum intensity. The MTF is the ratio of the modulation of the image to the modulation of the object and is a function of the spatial frequency, which is usually expressed in lp/mm. The modulation transfer function can be used to characterize the optical system, with a higher MTF indicating a better imaging quality of the system.

In FIG. 3, the abscissa represents spatial frequency in lp/mm; the ordinate indicates the degree of modulation. The embodiment of the utility model provides a requirement that is used for the camera lens of industrial machine vision to MTF is: the MTF of the central field is more than or equal to 35% @145lp/mm, and the MTF of the edge field is more than or equal to 10% @145 lp/mm. The uppermost curve in the MTF plot is the MTF curve for the central field, which can be seen to be > 35% MTF for the central field at 145 lp/mm. The lowest curve in the MTF plot is the MTF curve for the marginal field, which can be seen to be > 10% MTF for the marginal field at 145 lp/mm. It is visible, the embodiment of the utility model provides an imaging quality for industrial machine vision's camera lens can reach the designing requirement.

Fig. 4 is a distortion curve diagram of a lens for industrial machine vision according to an embodiment of the present invention. In the figure, the abscissa represents relative distortion in%; the ordinate represents the field angle.

The embodiment of the utility model provides a design requirement for camera lens of industrial machine vision does: the relative distortion over the full field of view is < 1%.

As shown in fig. 4, the relative distortion of the lens for industrial machine vision provided by the embodiment of the present invention is less than 0.8%, which can meet the design requirement.

Fig. 5 is an image plane relative illuminance diagram of a lens for industrial machine vision according to an embodiment of the present invention. As shown in fig. 5, the abscissa represents the angle of the field of view; the ordinate represents the image plane relative illuminance.

The embodiment of the utility model provides a design requirement for camera lens of industrial machine vision does: the relative illumination of the image plane in the whole view field range is more than or equal to 50 percent.

It can be seen from fig. 5 that the embodiment of the utility model provides a relative illuminance of image plane for industrial machine vision's camera lens in whole field of view within range > 50%, can reach the designing requirement.

Based on the embodiment of the utility model provides a camera lens for industrial machine vision, the utility model also provides an image acquisition part, it includes the arbitrary camera lens that is used for industrial machine vision of the aforesaid.

Illustratively, the image capturing component may include a monocular camera, a binocular camera, a 3D camera, a video camera, or the like, which is not particularly limited herein.

The foregoing is only an illustrative embodiment of the present invention, and any equivalent changes and modifications made by those skilled in the art without departing from the spirit and principles of the present invention should fall within the protection scope of the present invention.

Claims (10)

1. A lens for industrial machine vision is characterized by comprising a reverse telephoto lens group and a rear lens group which are coaxially arranged from an object side to an image side in sequence;

the anti-telephoto lens group comprises a first negative lens group and a second positive lens group which are arranged in sequence; the first negative lens group comprises at least one lens, and the second positive lens group comprises at least one lens; the rear lens group includes at least one lens.

2. A lens barrel for industrial machine vision according to claim 1, further comprising a stop disposed between the anti-telephoto lens group and the rear lens group.

3. A lens for industrial machine vision according to claim 2, characterized in that the aperture of the diaphragm is: 5 mm-9 mm.

4. A lens barrel for industrial machine vision according to claim 1, 2 or 3, wherein a distance between the reverse telephoto lens group and the rear lens group is 2mm to 13 mm; the distance between the first negative lens group and the second positive lens group is 0.8 mm-3 mm.

5. A lens barrel for industrial machine vision according to claim 1, 2 or 3, wherein the focal length of the first negative lens group is-27 mm to-15 mm; the focal length of the second positive lens group is 6-17 mm; the focal length of the rear lens group is 6 mm-17 mm.

6. A lens barrel for industrial machine vision according to claim 5, wherein the first negative lens group comprises a first negative lens and a second positive lens arranged in sequence, the focal length of the first negative lens is-12 mm to-8 mm; the focal length of the second positive lens is 50-57 mm; the distance between the first negative lens and the second positive lens is 2 mm-6 mm.

7. A lens barrel for industrial machine vision according to claim 6, wherein the second positive lens group comprises a third negative lens and a fourth positive lens arranged in sequence, the focal length of the third negative lens is-30 mm to-34 mm; the focal length of the fourth positive lens is 10-14 mm; the distance between the third negative lens and the fourth positive lens ranges from 3mm to 6 mm.

8. A lens barrel for industrial machine vision according to claim 7, wherein the rear lens group comprises a fifth positive lens and a sixth positive lens arranged in sequence, and the focal length of the fifth positive lens is 31mm to 35 mm; the focal length of the sixth positive lens is 18-22 mm; and the distance between the fifth positive lens and the sixth positive lens is 2-7 mm.

9. A lens barrel for industrial machine vision according to claim 8, wherein the first negative lens and the second positive lens each employ a spherical lens made of optical glass, and the third negative lens, the fourth positive lens, the fifth positive lens and the sixth positive lens each employ an aspherical lens made of optical plastic.

10. An image capturing element comprising a lens for industrial machine vision according to any one of claims 1 to 9.

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