CN214540213U - Optical lens, vision detection system and laser processing equipment - Google Patents

Abstract

The utility model relates to an optical lens, visual detection system and laser beam machining equipment. The optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens which are sequentially arranged from an object side to an image side, wherein the first lens has positive focal power and a double convex structure, the second lens has positive focal power and a meniscus structure, the third lens has negative focal power and a double concave structure, the fourth lens has positive focal power and a double convex structure, the fifth lens has positive focal power and a meniscus structure, the sixth lens has negative focal power and a double concave structure, the seventh lens has positive focal power and a meniscus structure, the eighth lens has positive focal power and a double convex structure, and the ninth lens has positive focal power and a double convex structure. The optical lens can be applied to a 4K line scan camera with higher resolution.

Description

Optical lens, vision detection system and laser processing equipment

Technical Field

The utility model relates to a precision finishing technical field especially relates to an optical lens, visual detection system and laser processing equipment.

Background

In the precision machining and manufacturing process, the product is necessarily positioned and detected, and if a common industrial lens is used, aberrations such as large distortion, parallax and the like exist, so that the positioning and detection precision is influenced. By using the telecentric lens, the special parallel light path design greatly reduces the problems, and the image magnification ratio can not be changed within a certain object distance range, so that the telecentric lens is very suitable for the field of precision machining.

However, most of the telecentric lenses have limited image space and field of view at present, and cannot be applied to high-resolution cameras.

SUMMERY OF THE UTILITY MODEL

Accordingly, it is necessary to provide an optical lens, a vision inspection system, and a laser processing apparatus for solving the problem that the conventional telecentric lens has a limited image space and a limited field of view and cannot be applied to a high-resolution camera.

An optical lens includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element, an eighth lens element, and a ninth lens element arranged in this order from an object side to an image side,

the first lens has positive focal power and a double convex structure, the second lens has positive focal power and a meniscus structure, the third lens has negative focal power and a double concave structure, the fourth lens has positive focal power and a double convex structure, the fifth lens has positive focal power and a meniscus structure, the sixth lens has negative focal power and a double concave structure, the seventh lens has positive focal power and a meniscus structure, the eighth lens has positive focal power and a double convex structure, and the ninth lens has positive focal power and a double convex structure.

The diameter of the image space field of the optical lens can reach 28mm, in other words, the optical lens has a larger field of view and can be suitable for a 4K line scan camera with higher resolution.

In one embodiment, the refractive index of the first lens is 1.716-1.752, the abbe number is 40-50, the refractive index of the second lens is 1.725-1.752, the abbe number is 40-50, the refractive index of the third lens is 1.725-1.752, the abbe number is 25-30, the refractive index of the fourth lens is 1.725-1.752, the abbe number is 40-50, the refractive index of the fifth lens is 1.712-1.735, the abbe number is 25-30, the refractive index of the sixth lens is 1.671-1.725, the abbe number is 25-35, the refractive index of the seventh lens is 1.671-1.725, the abbe number is 45-60, the refractive index of the eighth lens G8 is 1.613-1.671, the abbe number is 50-65, and the refractive index of the ninth lens is 1.613-1.613, and the abbe number is 50-65.

In one embodiment, the refractive index of the first lens is 1.73, the abbe number is 45.9, the refractive index of the second lens is 1.740, the abbe number is 44.2, the refractive index of the third lens is 1.736, the abbe number is 28.4, the refractive index of the fourth lens is 1.742, the abbe number is 45.01, the refractive index of the fifth lens is 1.728, the abbe number is 28.3, the refractive index of the sixth lens is 1.695, the abbe number is 30.51, the refractive index of the seventh lens is 1.691, the abbe number is 49.77, the refractive index of the eighth lens is 1.621, the abbe number is 60.11, the refractive index of the ninth lens is 1.634, and the abbe number is 56.9.

In one embodiment, the sixth lens and the seventh lens are cemented to each other.

In one embodiment, the optical lens further includes a diaphragm disposed between the fifth lens and the sixth lens and located on an image focal plane.

In one embodiment, the object-image conjugate distance of the optical lens is 432.49mm, the object-image conjugate distance of the optical lens is 432.49mm, the object-space working distance of the optical lens is 114mm, and the diameter of the image-space field of view is 28 mm.

In one embodiment, the magnification of the optical lens is 0.27.

In one embodiment, the first lens has a thickness of 12.860mm ± 5%, the second lens has a thickness of 9.888mm ± 5%, the third lens has a thickness of 2.937mm ± 5%, the fourth lens has a thickness of 10.000mm ± 5%, the fifth lens has a thickness of 2.210mm ± 5%, the sixth lens has a thickness of 2.000mm ± 5%, the seventh lens has a thickness of 7.916mm ± 5%, the eighth lens has a thickness of 10.000mm ± 5%, and the ninth lens has a thickness of 9.248mm ± 5%.

The utility model also provides a visual detection system, including the camera with optical lens, optical lens still includes the lens cone, first lens the second lens the third lens the fourth lens the fifth lens the diaphragm the sixth lens the seventh lens the eighth lens reach the ninth lens set gradually in the lens cone, the end of lens cone is equipped with the hickey, so that with the camera is connected.

The utility model also provides a laser beam machining equipment, include the vision detecting system.

Drawings

FIG. 1 is a diagram illustrating an optical lens assembly according to an embodiment;

FIG. 2 is a field curvature distortion diagram of the optical lens shown in FIG. 1;

FIG. 3 is a diagram of an optical transfer function of the optical lens system shown in FIG. 1;

fig. 4 is a vertical axis chromatic aberration diagram of the optical lens shown in fig. 1.

The following detailed description of the invention will be made in conjunction with the above drawings.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

The utility model provides a laser processing equipment, including vision detection system and laser beam machining head. The visual detection system is used for positioning and detecting a workpiece to be processed, and the detection precision of the visual detection system directly influences the processing quality.

The working principle of the visual inspection system is that a computer is utilized to simulate the visual function of a human to extract information from an image of an objective object, and the information is processed and understood to be finally used for actual inspection. The visual inspection system comprises a light source, an optical lens, a camera and an image processing module. The optical lens comprises a lens barrel, and the tail end of the lens barrel is provided with a threaded interface so as to be connected with a camera. The work flow of the visual inspection system is as follows: firstly, a camera is adopted to obtain an image signal of an object, then a digital signal is obtained through A/D conversion and is transmitted to an image processing module, the operation is carried out according to information such as pixel distribution, brightness and color to extract the characteristics of the object, and then a judgment result is output according to a preset judgment criterion.

The optical lens is used as a core component of a visual inspection system and has direct influence on imaging quality. The utility model provides an optical lens is thing side telecentric lens, and optical lens includes first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, diaphragm C, sixth lens 6, seventh lens 7, eighth lens 8 and the ninth lens 9 that follow optical axis OA and arrange in proper order from thing side OB to image side IM to diaphragm C is located image side focal plane. The optical lens is an object space telecentric lens, the chief ray of the object space is parallel to the optical axis, and the convergence center of the chief ray is positioned at the infinite distance of the object space. When the object distance changes, the image distance changes correspondingly, but the image height does not change, so that the measured size of the object does not change.

The first lens 1 has a positive focal power and a double convex structure, the second lens 2 has a positive focal power and a meniscus structure, the third lens 3 has a negative focal power and a double concave structure, the fourth lens 4 has a positive focal power and a double convex structure, the fifth lens 5 has a positive focal power and a meniscus structure, the sixth lens 6 has a negative focal power and a double concave structure, the seventh lens 7 has a positive focal power and a meniscus structure, the eighth lens 8 has a positive focal power and a double convex structure, and the ninth lens 9 has a positive focal power and a double convex structure.

The diameter of the image space field of the optical lens can reach 28mm, in other words, the optical lens has a larger field of view and can be suitable for a 4K line scan camera with higher resolution.

The refractive index of the first lens 1 is 1.716-1.752, the Abbe number is 40-50, the refractive index of the second lens 2 is 1.725-1.752, the Abbe number is 40-50, the refractive index of the third lens 3 is 1.725-1.752, the Abbe number is 25-30, the refractive index of the fourth lens 4 is 1.725-1.752, the Abbe number is 40-50, the refractive index of the fifth lens 5 is 1.712-1.735, the Abbe number is 25-30, the refractive index of the sixth lens 6 is 1.671-1.725, the Abbe number is 25-35, the refractive index of the seventh lens 7 is 1.671-1.725, the Abbe number is 45-60, the refractive index of the eighth lens 8G8 is 1.613-1.671, the Abbe number is 50-65, the refractive index of the ninth lens 9 is 1.613-1.671, and the Abbe number is 50-65.

The sixth lens 6 and the seventh lens 7 are cemented to each other.

When the object side OB working distance of the optical lens is 114mm, the diameter of the image side field of view is 28 mm.

Examples

The optical lens includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, and a ninth lens 9, which are arranged in order from an object side OB to an image side IM. The first lens 1 has a front surface facing the object side OB and a rear surface facing the image side IM. The second lens 2 has a front surface facing the object side OB and a rear surface facing the image side IM. The third lens 3 has a front surface facing the object side OB and a rear surface facing the image side IM. The fourth lens 4 has a front surface facing the object side OB and a rear surface facing the image side IM. The fifth lens 5 has a front surface facing the object side OB and a rear surface facing the image side IM. The sixth lens 6 has a front surface facing the object side OB and a rear surface facing the image side IM. The seventh lens 7 has a front surface facing the object side OB and a rear surface facing the image side IM. The eighth lens 8 has a front surface facing the object side OB and a rear surface facing the image side IM. The ninth lens 9 has a front surface facing the object side OB and a rear surface facing the image side IM.

The following table lists various parameters of the optical lens of the present embodiment, including the radius of curvature, thickness, and material (refractive index/abbe number), where the thickness values in the table represent the distance from the front surface to the back surface of the lens along the optical axis OA.

TABLE 1 radius of curvature of front and rear surfaces of lens, thickness of lens, refractive index and Abbe number

According to table 1 in conjunction with fig. 1, the object side OB working distance of the optical lens is 114mm, which is the distance along the optical axis OA from the object side OB to the front surface of the first lens 1.

The radius of curvature of the front surface of the first lens 1 is 226.176mm, the radius of curvature of the rear surface is-134.591 mm, and the error range is +/-5%; the thickness of the first lens 1 is 12.860mm, and the error is in the range of +/-5%; the distance along the optical axis OA from the rear surface of the first lens 1 to the front surface of the second lens 2 is 142.385 mm; the refractive index of the first lens 1 was 1.73, and the abbe number was 45.9.

Note that a positive value of the radius of curvature indicates that the lens surface is convex toward the object side OB, and a negative value of the radius of curvature indicates that the lens surface is convex toward the image side IM.

The radius of curvature of the front surface of the second lens 2 is 18.946mm, and the radius of curvature of the rear surface is 14.421 mm; the thickness of the second lens 2 is 9.888mm with a tolerance in the range of ± 5%, and the distance along the optical axis OA from the rear surface of the second lens 2 to the front surface of the third lens 3 is 3.658 mm; the refractive index of the second lens 2 was 1.740, and the abbe number was 44.2.

The radius of curvature of the front surface of the third lens 3 is-149.153 mm, and the radius of curvature of the rear surface is 22.095 mm; the thickness of the third lens 3 is 2.937mm with a tolerance in the range of ± 5%, and the distance along the optical axis OA from the rear surface of the third lens 3 to the front surface of the fourth lens 4 is 8.745 mm; the refractive index of the third lens 3 was 1.736, and the abbe number was 28.4.

The radius of curvature of the front surface of the fourth lens 4 is 46.660mm, and the radius of curvature of the rear surface is-78.138 mm; the thickness of the fourth lens 4 is 10.000mm with a tolerance in the range of ± 5%, and the distance along the optical axis OA from the rear surface of the fourth lens 4 to the front surface of the fifth lens 5 is 0.592 mm; the refractive index of the fourth lens 4 is 1.742, and the abbe number is 45.01.

The curvature radius of the front surface of the fifth lens 5 is 27.472mm, and the curvature radius of the rear surface is 45.788 mm; the thickness of the fifth lens 5 is 2.210mm with an error in the range of ± 5%, and the distance from the rear surface of the fifth lens 5 to the diaphragm C along the optical axis OA is 10.069 mm; the refractive index of the fifth lens 5 is 1.728, and the abbe number is 28.3.

The distance along the optical axis OA from the diaphragm C to the front surface of the sixth lens 6 is 0.555.

The curvature radius of the front surface of the sixth lens 6 is-221.853 mm, and the curvature radius of the rear surface is 15.349 mm; the thickness of the sixth lens 6 is 2.000mm, the error is within the range of +/-5%, the back surface of the sixth lens 6 and the front surface of the seventh lens 7 are mutually glued, and the distance is 0; the sixth lens 6 has a refractive index of 1.695 and an abbe number of 30.51.

The curvature radius of the front surface of the seventh lens 7 is 15.349mm, and the curvature radius of the rear surface is 30.448 mm; the thickness of the seventh lens 7 is 7.916mm with an error in the range of ± 5%, and the distance along the optical axis OA from the rear surface of the seventh lens 7 to the front surface of the eighth lens 8 is 4.954 mm; the refractive index of the seventh lens 7 was 1.691, and the abbe number was 49.77.

The curvature radius of the front surface of the eighth lens 8 is 101.775mm, and the curvature radius of the rear surface is-40.110 mm; the thickness of the eighth lens 8 is 10.000mm with a tolerance in the range of ± 5%, and the distance along the optical axis OA from the rear surface of the eighth lens 8 to the front surface of the ninth lens 9 is 36.539 mm; the eighth lens 8 has a refractive index of 1.621 and an abbe number of 60.11.

The curvature radius of the front surface of the ninth lens 9 is 82.990mm, and the curvature radius of the rear surface is-84.772 mm; the thickness of the ninth lens 9 is 9.248mm, and the error is within a range of ± 5%, and the distance from the rear surface of the ninth lens 9 to the image plane along the optical axis OA is 43.393 mm; the refractive index of the ninth lens 9 is 1.634, and the abbe number is 56.9.

Fig. 2 is a field curvature distortion diagram of an optical lens, when the optical lens has field curvature, the intersection point of the whole light beam does not coincide with an ideal image point, although a clear image point can be obtained at each specific point, the whole image plane is a curved surface, so that the whole image plane cannot be seen clearly, and the observation of a picture and the shooting are difficult. Distortion is actually a generic term for the intrinsic perspective distortion of an optical lens, i.e. distortion due to perspective, which is very detrimental to the imaging quality. As can be seen from fig. 2, the field curvature is within 0.1mm, and the distortion is less than 0.008%, which ensures that the picture shot by the optical lens is not curved and the picture is flat and straight without visible distortion.

Fig. 3 is a graph of an Optical Transfer Function (MTF), which is a Function representing relative changes of modulation degree and lateral phase shift in an imaging process with spatial frequency as a variable. The optical transfer function is a filtered transformation of the optical system to a spatial spectrum. FIG. 3 represents the optical transfer function value for an object-side working distance of 114mm, an aperture (F/#) of 6.5, and a field-of-view circle diameter of 28 mm. Wherein, the aperture (F/#) is the ratio of the focal length of the lens to the diameter of the entrance pupil. The aperture is used for determining the light inlet quantity of the lens and adjusting the quantity of light rays entering the lens, and the smaller the numerical value of the aperture is, the larger the aperture is, the more the light inlet quantity is. Conversely, the larger the numerical value of the aperture, the smaller the aperture, and the smaller the amount of light entering. When the spatial frequency is 150lp/mm, the corresponding MTF value reaches 0.3, which indicates that the optical lens can well distinguish the contour of the object in the frequency range, and the whole picture shot by the optical lens is clearer.

Fig. 4 is a vertical axis chromatic aberration diagram of an optical lens, which is also called chromatic aberration, and is a serious defect of lens imaging, where chromatic aberration is simply a difference in color, and monochromatic light does not generate chromatic aberration when polychromatic light is used as a light source. The maximum value of the ordinate in fig. 4 is 14mm, which indicates that the chromatic aberration of the full field of view is within the range of the airy disk, thereby ensuring that no visible color difference exists in the range of the field of view of the whole picture and meeting the design requirements.

Furthermore, the utility model discloses optical lens's telecentric degree is less than 0.03, has realized telecentric lens's design requirement. The telecentricity refers to an included angle between an object space main ray and an optical axis, and the smaller the telecentricity is, the better the perspective error can be eliminated, so that the measurement error is reduced.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. An optical lens includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element, an eighth lens element, and a ninth lens element arranged in this order from an object side to an image side,

the first lens has positive focal power and a double convex structure, the second lens has positive focal power and a meniscus structure, the third lens has negative focal power and a double concave structure, the fourth lens has positive focal power and a double convex structure, the fifth lens has positive focal power and a meniscus structure, the sixth lens has negative focal power and a double concave structure, the seventh lens has positive focal power and a meniscus structure, the eighth lens has positive focal power and a double convex structure, and the ninth lens has positive focal power and a double convex structure.

2. An optical lens according to claim 1, wherein the first lens has a refractive index of 1.716-1.752 and an Abbe number of 40-50, the refractive index of the second lens is 1.725-1.752, the Abbe number is 40-50, the refractive index of the third lens is 1.725-1.752, the Abbe number is 25-30, the refractive index of the fourth lens is 1.725-1.752, the Abbe number is 40-50, the fifth lens has a refractive index of 1.712-1.735, an Abbe number of 25-30, the sixth lens has a refractive index of 1.671 to 1.725 and an Abbe number of 25 to 35, the seventh lens has a refractive index of 1.671 to 1.725, an Abbe number of 45 to 60, the refractive index of the eighth lens G8 is 1.613-1.671, the Abbe number is 50-65, the refractive index of the ninth lens is 1.613-1.671, and the Abbe number is 50-65.

3. The optical lens according to claim 1, wherein the refractive index of the first lens is 1.73, the abbe number is 45.9, the refractive index of the second lens is 1.740, the abbe number is 44.2, the refractive index of the third lens is 1.736, the abbe number is 28.4, the refractive index of the fourth lens is 1.742, the abbe number is 45.01, the refractive index of the fifth lens is 1.728, the abbe number is 28.3, the refractive index of the sixth lens is 1.695, the abbe number is 30.51, the refractive index of the seventh lens is 1.691, the abbe number is 49.77, the refractive index of the eighth lens is 1.621, the abbe number is 60.11, the refractive index of the ninth lens is 1.634, and the abbe number is 56.9.

4. An optical lens according to claim 1, characterized in that the sixth lens and the seventh lens are cemented to each other.

5. An optical lens according to claim 1, characterized in that the optical lens further comprises a diaphragm which is disposed between the fifth lens and the sixth lens and is located on an image space focal plane.

6. An optical lens barrel according to claim 1, wherein the first lens has a thickness of 12.860mm ± 5%, the second lens has a thickness of 9.888mm ± 5%, the third lens has a thickness of 2.937mm ± 5%, the fourth lens has a thickness of 10.000mm ± 5%, the fifth lens has a thickness of 2.210mm ± 5%, the sixth lens has a thickness of 2.000mm ± 5%, the seventh lens has a thickness of 7.916mm ± 5%, the eighth lens has a thickness of 10.000mm ± 5%, and the ninth lens has a thickness of 9.248mm ± 5%.

7. An optical lens according to claim 1, characterized in that the magnification of the optical lens is 0.27.

8. An optical lens according to claim 1, characterized in that the object-image conjugate distance of the optical lens is 432.49mm, the object-side working distance of the optical lens is 114mm, and the diameter of the image-side field of view is 28 mm.

9. A visual inspection system, comprising a camera and the optical lens of any one of claims 1 to 8, wherein the optical lens further comprises a lens barrel and a diaphragm, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the diaphragm, the sixth lens, the seventh lens, the eighth lens and the ninth lens are sequentially disposed in the lens barrel, and a threaded interface is disposed at a distal end of the lens barrel so as to connect to the camera.

10. A laser machining apparatus comprising the visual inspection system of claim 9.

Images