Machine vision lens

Abstract

The utility model discloses a machine vision lens which comprises a meniscus negative lens A, a biconvex positive lens B, a meniscus positive lens C, a diaphragm S, a biconcave negative lens D, a plano-convex positive lens E and a biconvex positive lens F which are sequentially and coaxially arranged from an object plane to an imaging plane. The concave surface of the meniscus negative lens A faces the imaging surface; the biconvex positive lens B comprises two convex lenses of which the convex surfaces are oppositely arranged; the incident surface and the emergent surface of the biconcave negative lens D are concave surfaces; the incident plane of the plano-convex positive lens E is a plane, the emergent plane of the plano-convex positive lens E is a convex surface, and the convex surface of the plano-convex positive lens E faces the imaging surface; and the biconvex positive lens F comprises two convex lenses of which the convex surfaces are oppositely arranged. The machine vision lens of the utility model realizes imaging distortion within 2% and image space resolution of 2.5 [mu] m.

Description

Technical Field

[0001] This utility model relates to the field of optical imaging technology, and in particular to a machine vision lens. Background Technology

[0002] Machine vision lenses are the eyes of artificial intelligence and AR systems. In a machine vision system, the imaging lens is responsible for imaging the physical scene onto the camera sensor. The camera then converts the light signals into digital images, which are further processed and analyzed by artificial intelligence. With the development of artificial intelligence and AR technologies, the performance requirements for imaging lenses are gradually increasing, demanding not only high resolution and low distortion but also low manufacturing costs. Reducing the cost of machine vision lenses requires reducing the number of lens elements. Utility Model Content

[0003] The purpose of this invention is to provide a machine vision lens.

[0004] The technical solution adopted in this utility model is:

[0005] A machine vision lens converges light from an object surface to an imaging surface; it includes a meniscus negative lens A, a biconvex positive lens B, a meniscus positive lens C, an aperture S, a biconcave negative lens D, a plano-convex positive lens E, and a biconvex positive lens F arranged coaxially from the object surface to the imaging surface; the concave surface of the meniscus negative lens A faces the imaging surface; the biconvex positive lens B includes two convex lenses with convex surfaces facing each other; the incident and exit surfaces of the biconcave negative lens D are both concave; the incident surface of the plano-convex positive lens E is planar and the exit surface is convex, with the convex surface of the plano-convex positive lens E facing the imaging surface; the biconvex positive lens F includes two convex lenses with convex surfaces facing each other.

[0006] Furthermore, the incident surface of the meniscus negative lens A is a plane parallel to the object plane, and the exit surface of the meniscus negative lens A is a concave surface.

[0007] Furthermore, the system focal length f of the machine vision lens satisfies the following condition: f = 12.00 ± 0.05 mm.

[0008] Furthermore, the focal length f of the meniscus negative lens A A The following condition must be met: 10.00mm < |f A |<20.00mm.

[0009] Furthermore, the focal length f of the biconvex positive lens B B The following condition must be met: 15.00mm < |f B |<25.0mm.

[0010] Furthermore, the focal length f of the meniscus lens C C The following condition must be met: 20.00mm < |fC |<30.00mm.

[0011] Furthermore, the focal length f of the biconcave negative lens D D The following condition must be met: 5.00mm < |f D |<10.00mm.

[0012] Furthermore, the focal length f of the plano-convex positive lens E E The following condition must be met: 15.00mm < |f E |<25.00mm.

[0013] Furthermore, the focal length f of the biconvex positive lens F F The following condition must be met: 15.00mm < |f F |<25.00mm.

[0014] This invention employs the above technical solution, targeting a 12mm focal length industrial lens with a 6-element structure, achieving an aperture of F2.8 and a 42° field of view. The machine vision lens of this invention can achieve imaging distortion within 2% and an image resolution of 2.5µm. Attached Figure Description

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments;

[0016] Figure 1 This is a schematic diagram of the structure of a machine vision lens according to the present invention;

[0017] Figure 2 This is a schematic diagram of the optical transfer function (MTF) of this invention at a resolution of 200 lp / mm;

[0018] Figure 3 This is a schematic diagram of the relative illumination performance of this utility model;

[0019] Figure 4 This is a schematic diagram showing the distortion size of this utility model. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0021] like Figures 1 to 4As shown in one example, this utility model discloses a machine vision lens, which includes a meniscus negative lens A, a biconvex positive lens B, a meniscus positive lens C, an aperture S, a biconcave negative lens D, a plano-convex positive lens E, and a biconvex positive lens F arranged coaxially from the object plane to the imaging plane; the concave surface of the meniscus negative lens A faces the imaging plane; the biconvex positive lens B includes two convex lenses with convex surfaces facing each other; the incident surface and the exit surface of the biconcave negative lens D are both concave; the incident surface of the plano-convex positive lens E is planar and the exit surface is convex, with the convex surface of the plano-convex positive lens E facing the imaging plane; the biconvex positive lens F includes two convex lenses with convex surfaces facing each other.

[0022] Furthermore, the incident surface of the meniscus negative lens A is a plane parallel to the object plane, and the exit surface of the meniscus negative lens A is a concave surface.

[0023] Furthermore, the system focal length f of the machine vision lens satisfies the following condition: f = 12.00 ± 0.05 mm.

[0024] Furthermore, the focal length f of the meniscus negative lens A A The following condition must be met: 10.00mm < |f A |<20.00mm.

[0025] Furthermore, the focal length f of the biconvex positive lens B B The following condition must be met: 15.00mm < |f B |<25.0mm.

[0026] Furthermore, the focal length f of the meniscus lens C C The following condition must be met: 20.00mm < |f C |<30.00mm.

[0027] Furthermore, the focal length f of the biconcave negative lens D D The following condition must be met: 5.00mm < |f D |<10.00mm.

[0028] Furthermore, the focal length f of the plano-convex positive lens E E The following condition must be met: 15.00mm < |f E |<25.00mm.

[0029] Furthermore, the focal length f of the biconvex positive lens F F The following condition must be met: 15.00mm < |f F |<25.00mm.

[0030] Example: See Figure 1A machine vision lens, from an object plane to an image plane, along the direction of light incidence, is provided with a meniscus negative lens A, a biconvex positive lens B, a meniscus positive lens C, a diaphragm S, a biconcave negative lens D, a plano-convex positive lens E and a biconvex positive lens F in sequence. The system focal length f of the machine vision lens of the embodiment is 12.00 mm, the focal length f of the meniscus negative lens A is -14.21 mm, the focal length f of the biconvex positive lens B is 19.98 mm, the focal length f of the meniscus positive lens C is 26.83 mm, the diaphragm S adjusts the light flux, the focal length f of the biconcave negative lens D is -7.75 mm, the focal length f of the plano-convex positive lens E is 17.46 mm, and the focal length f of the biconvex positive lens F is 17.60 mm. A B C D E F

[0031] Table 1. Various lens parameters and air gaps of the embodiment:

[0032]

[0033] According to the layout and the various lens parameters in Table 1, an optical design program is used to trace the light from the object plane to the image plane. The light emitted from the object plane passes through the meniscus negative lens A, the biconvex positive lens B, the meniscus positive lens C, the diaphragm S, the biconcave negative lens D, the plano-convex positive lens E and the biconvex positive lens F, and converges to the image plane. After tracing the light, the performance of the lens of the embodiment can be calculated and analyzed.

[0034] Modulation transfer function (MTF) is the most important indicator for evaluating the imaging quality of an optical system. It quantifies the ability of an optical system to transfer image details, providing a scientific basis for optical design, manufacturing and evaluation. The higher the MTF value, the more details the system can clearly transfer, which is related to whether the machine vision lens can provide correct input for artificial intelligence. Figure 2 As shown in FIG. 6, the resolution of the entire object plane is greater than 0.3 in the meridional and sagittal directions at 200 lp / mm, which can distinguish image elements below 2.5 um; relative luminance describes the change in light flux at different object planes, and if the relative luminance is too small, the edge image will be too dark, as shown in FIG. 7, the relative luminance of the entire field of view is better than 0.6, meeting the requirements of pattern recognition; distortion describes the degree of deformation of the projected image, and the imaging requirement is usually less than 2.0%, as shown in FIG. 8, the distortion of the entire field of view is less than 2.0%, so that the image is not deformed, avoiding misjudgment by artificial intelligence. Figure 3 Figure 4

[0035] ​​​​​​​​The wavelength is visible light, the light FNO is better than 2.8, the optical transfer function MTF is greater than 0.3@200lp / mm, the object height 2h is greater than 9.0mm, the total length L is less than 50mm, the full field of view relative luminance is better than 0.6, and the distortion is less than 2.0%.

[0036] The utility model discloses above technical scheme aims at 12mm focal length's industrial camera lens, adopts 6 piece formula's structure, and it can realize F2.8's aperture and 42's field of view.

[0037] Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

Claims

1. A machine vision lens that converges light from an object surface onto an imaging surface; characterized in that: The lens comprises a meniscus negative lens A, a biconvex positive lens B, a meniscus positive lens C, an aperture stop S, a biconcave negative lens D, a plano-convex positive lens E, and a biconvex positive lens F, arranged coaxially from the object plane to the image plane. The concave surface of the meniscus negative lens A faces the image plane. The biconvex positive lens B comprises two convex lenses with their convex surfaces facing each other. The incident and exit surfaces of the biconcave negative lens D are both concave. The incident surface of the plano-convex positive lens E is planar, and the exit surface is convex. The convex surface of the plano-convex positive lens E faces the image plane. The biconvex positive lens F comprises two convex lenses with their convex surfaces facing each other.

2. The machine vision lens according to claim 1, characterized in that: The incident surface of the meniscus negative lens A is a plane parallel to the object plane, and the exit surface of the meniscus negative lens A is a concave surface.

3. A machine vision lens according to claim 1, characterized in that: System focal length of machine vision lenses The following conditions must be met: .

4. A machine vision lens according to claim 1, characterized in that: Focal length of meniscus negative lens A The following conditions must be met: .

5. A machine vision lens according to claim 1, characterized in that: The focal length of the biconvex positive lens B The following conditions must be met: .

6. A machine vision lens according to claim 1, characterized in that: Focal length of meniscus lens C The following conditions must be met: .

7. A machine vision lens according to claim 1, characterized in that: The focal length of the biconcave negative lens D The following conditions must be met: .

8. A machine vision lens according to claim 1, characterized in that: The focal length of the plano-convex positive lens E The following conditions must be met: .

9. A machine vision lens according to claim 1, characterized in that: The focal length of the biconvex positive lens F The following conditions must be met: .

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