A large-aperture, large-target-surface high-definition fixed-focus industrial lens

Abstract

The present application relates to a kind of big aperture, big target surface high-definition fixed focus industrial lens, optical system is sequentially spaced from front to back along the incident light path and is sequentially arranged first lens to seventh lens, diaphragm, eighth lens to twelfth lens;First lens is meniscus glass spherical lens, second lens is double convex glass spherical lens, third lens is meniscus glass spherical lens, fourth lens is meniscus glass spherical lens, fifth lens is meniscus glass spherical lens, sixth lens is double concave glass spherical lens, seventh lens is double convex glass spherical lens, eighth lens is meniscus glass spherical lens, ninth lens is double convex glass spherical lens, tenth lens is meniscus glass spherical lens, eleventh lens is meniscus glass spherical lens, twelfth lens is meniscus glass spherical lens, third lens and fourth lens are glued, sixth lens and seventh lens are glued, eighth lens and ninth lens are glued, tenth lens and eleventh lens are glued.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial lens, in particular to a large-aperture, large-target high-definition fixed-focus industrial lens. BACKGROUND

[0002] In recent years, with the development of automation industry, machine vision has achieved rapid growth, and the application field of industrial lens is more and more extensive. The market requires higher and higher image quality of the lens, usually requires high-definition resolution, small image distortion, and good imaging effect at different working distances. However, most of the fixed-focus industrial lenses on the market are only megapixels, and few are ten-megapixel level. Most of the lenses have a focal length f greater than 2.0, a small aperture, a large chromatic aberration, insufficient brightness, a small target surface, a complex structure, and cannot realize the problem of portable fixed-focus industrial lens. And the imaging effect is quite different at different working distances. SUMMARY

[0003] (I) Technical problems to be solved

[0004] In order to solve the above problems of the prior art, the present application provides a large-aperture, large-target high-definition fixed-focus industrial lens.

[0005] (II) Technical scheme

[0006] In order to achieve the above purpose, the main technical scheme adopted by the present application includes: a large-aperture, large-target high-definition fixed-focus industrial lens, the optical system of the lens is composed of a negative focal length first lens, a positive focal length second lens, a negative focal length third lens, a positive focal length fourth lens, a negative focal length fifth lens, a negative focal length sixth lens, a positive focal length seventh lens, a diaphragm, a negative focal length eighth lens, a positive focal length ninth lens, a positive focal length tenth lens, a negative focal length eleventh lens and a positive focal length twelfth lens which are sequentially and spaced apart along the incident light path from front to back.

[0007] The first lens is a meniscus glass spherical lens, the second lens is a biconvex glass spherical lens, the third lens is a meniscus glass spherical lens, the fourth lens is a meniscus glass spherical lens, the fifth lens is a meniscus glass spherical lens, the sixth lens is a biconcave glass spherical lens, the seventh lens is a biconvex glass spherical lens, the eighth lens is a meniscus glass spherical lens, the ninth lens is a biconvex glass spherical lens, the tenth lens is a meniscus glass spherical lens, the eleventh lens is a meniscus glass spherical lens, the twelfth lens is a meniscus glass spherical lens, the third lens and the fourth lens are cemented to form a first cemented lens, the sixth lens and the seventh lens are cemented to form a second cemented lens, the eighth lens and the ninth lens are cemented to form a third cemented lens, and the tenth lens and the eleventh lens are cemented to form a fourth cemented lens.

[0008] (Three) beneficial effects

[0009] The beneficial effects of the present application are:

[0010] (1) By using 4 groups of cemented lens groups to correct chromatic aberration, the lens structure is compact.

[0011] (2) By using the combination of 7 lenses in the front group and 5 lenses in the rear group, the positive and negative focal lengths are matched, the structure is simple and reasonable, and the problem of insufficient clarity, small aperture, small target surface, and complex structure in the prior art is solved, and the problem of realizing a portable fixed focus industrial lens is solved. BRIEF DESCRIPTION OF DRAWINGS

[0012] Fig. 1 is a schematic diagram of the lens optical path structure of a large-aperture, large-target-surface, high-definition fixed focus industrial lens of the present application;

[0013] Fig. 2 is an MTF curve diagram of a large-aperture, large-target-surface, high-definition fixed focus industrial lens of the present application at a working object distance of 350mm, wherein the X-axis is the spatial frequency of the MTF curve, and the unit is lp / mm, and the Y-axis is the modulation transfer function value of the MTF curve;

[0014] Fig. 3 is a Field Curv / Dist curve diagram of a large-aperture, large-target-surface, high-definition fixed focus industrial lens of the present application at a working object distance of 350mm;

[0015] BRIEF DESCRIPTION OF DRAWINGS

[0016] A-1, first lens; A-2, second lens; A-3, third lens; A-4, fourth lens; A-5, fifth lens; A-6, sixth lens; A-7, seventh lens; STO, stop; B-8, eighth lens; B-9, ninth lens; B-10, tenth lens; B-11, eleventh lens; B-12, twelfth lens; IMA, image plane. DETAILED DESCRIPTION

[0017] In order to better explain the present application, so as to be understood, the present application is described in detail below by specific embodiments, combined with the drawings.

[0018] Please refer to Figs. 1-3 Fig. 1 shows a large-aperture, large-target high-definition fixed-focus industrial lens, the optical system of the lens is composed of a negative first lens, a positive second lens, a negative third lens, a positive fourth lens, a negative fifth lens, a negative sixth lens, a positive seventh lens, a stop, a negative eighth lens, a positive ninth lens, a positive tenth lens, a negative eleventh lens and a positive twelfth lens arranged in sequence along the incident light path from front to back at intervals;

[0019] The first lens is a meniscus glass spherical lens, the second lens is a double-convex glass spherical lens, the third lens is a meniscus glass spherical lens, the fourth lens is a meniscus glass spherical lens, the fifth lens is a meniscus glass spherical lens, the sixth lens is a double-concave glass spherical lens, the seventh lens is a double-convex glass spherical lens, the eighth lens is a meniscus glass spherical lens, the ninth lens is a double-convex glass spherical lens, the tenth lens is a meniscus glass spherical lens, the eleventh lens is a meniscus glass spherical lens, and the twelfth lens is a meniscus glass spherical lens. The third lens and the fourth lens are cemented to form a first cemented lens, the sixth lens and the seventh lens are cemented to form a second cemented lens, the eighth lens and the ninth lens are cemented to form a third cemented lens, and the tenth lens and the eleventh lens are cemented to form a fourth cemented lens.

[0020] As can be seen from the above description, by using 4 groups of cemented lenses to correct chromatic aberration, the lens structure is compact. By using the combination of 7 lenses in the front group and 5 lenses in the rear group, the positive and negative focal lengths are matched, the structure is simple and reasonable, and the problem of insufficient clarity, small aperture, small target surface, and complex structure in the prior art is solved, and the problem of realizing a portable fixed-focus industrial lens cannot be solved.

[0021] Further, the air gap between the first lens and the second lens is 17.26 mm, the air gap between the second lens and the third lens is 0.1 mm, the air gap between the fourth lens and the fifth lens is 0.768 mm, the air gap between the fifth lens and the sixth lens is 1.657 mm, the air gap between the seventh lens and the eighth lens is 4 mm, the air gap between the ninth lens and the tenth lens is adjustable, and the air gap between the eleventh lens and the twelfth lens is 0.878 mm.

[0022] As can be seen from the above description, the optical system composed of the above lenses has a short total light path length, so that the structure of the lens is compact.

[0023] Further, when the working object distance changes, the lens focuses by adjusting the air gap between the ninth lens and the tenth lens. When the working object distance is 200 mm, the air gap between the ninth lens and the tenth lens is 4.6 mm; when the working object distance is 350 mm, the air gap between the ninth lens and the tenth lens is 2.835 mm; and when the working object distance is infinity, the air gap between the ninth lens and the tenth lens is 0.418 mm.

[0024] As can be seen from the above description, based on the floating focusing technology of the ninth lens and the tenth lens, compared with conventional rear focusing, the chromatic aberration can be greatly reduced from near and far distances, and good image quality can be obtained at different working object distances.

[0025] Further, the optical system focal length of the lens is set as f, and the system focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, and the twelfth lens are f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, and f12, respectively. The optical system focal length f of the lens satisfies the following conditions: -81 mm < f1 < -80 mm; 42 mm < f2 < 43 mm; f3 = -85.185 mm; f4 = 30.128 mm; -27 mm < f5 < -26 mm; f6 = -21.449 mm; f7 = 22.179 mm; f8 = -28.498 mm; f9 = 15.157 mm; f10 = 54.05 mm; f11 = -35.953 mm; and f12 = 76.282 mm.

[0026] From the above description, by reasonably distributing the focal length of the optical system according to the above proportion, the imaging system can have small spherical aberration and field curvature at the same time, and the image quality of the on-axis and off-axis fields can be ensured. Moreover, the optical system can have reasonable correction and balance of the aberration in the wavelength range of 400-700 nm. In addition, the optical system has a large optical back focal length, and can be used with various cameras.

[0027] Embodiment one

[0028] Please refer to Figs. 1-3 A large-aperture, large-target high-definition fixed-focus industrial lens is shown in FIG. 1. The optical system of the lens is composed of a negative focal length first lens A-1, a positive focal length second lens A-2, a negative focal length third lens A-3, a positive focal length fourth lens A-4, a negative focal length fifth lens A-5, a negative focal length sixth lens A-6, a positive focal length seventh lens A-7, a stop STO, a negative focal length eighth lens B-8, a positive focal length ninth lens B-9, a positive focal length tenth lens B-10, a negative focal length eleventh lens B-11, and a positive focal length twelfth lens B-12 arranged in sequence along the incident light path from front to back.

[0029] The first lens A-1 is a meniscus glass spherical lens, the second lens A-2 is a biconvex glass spherical lens, the third lens A-3 is a meniscus glass spherical lens, the fourth lens A-4 is a meniscus glass spherical lens, the fifth lens A-5 is a meniscus glass spherical lens, the sixth lens A-6 is a biconcave glass spherical lens, the seventh lens A-7 is a biconvex glass spherical lens, the eighth lens B-8 is a meniscus glass spherical lens, the ninth lens B-9 is a biconvex glass spherical lens, the tenth lens B-10 is a meniscus glass spherical lens, the eleventh lens B-11 is a meniscus glass spherical lens, and the twelfth lens B-12 is a meniscus glass spherical lens. The third lens A-3 and the fourth lens A-4 are cemented to form a first cemented lens, the sixth lens A-6 and the seventh lens A-7 are cemented to form a second cemented lens, the eighth lens B-8 and the ninth lens B-9 are cemented to form a third cemented lens, and the tenth lens B-10 and the eleventh lens B-11 are cemented to form a fourth cemented lens.

[0030] In the embodiment, the air gap between the first lens A-1 and the second lens A-2 is 17.26 mm, the air gap between the second lens A-2 and the third lens A-3 is 0.1 mm, the air gap between the fourth lens A-4 and the fifth lens A-5 is 0.768 mm, the air gap between the fifth lens A-5 and the sixth lens A-6 is 1.657 mm, the air gap between the seventh lens A-7 and the eighth lens B-8 is 4 mm, the air gap between the ninth lens B-9 and the tenth lens B-10 is adjustable, and the air gap between the eleventh lens B-11 and the twelfth lens B-12 is 0.878 mm.

[0031] In the embodiment, when the working object distance changes, the lens focuses by adjusting the air gap between the ninth lens B-9 and the tenth lens B-10. When the working object distance is 200 mm, the air gap between the ninth lens B-9 and the tenth lens B-10 is 4.6 mm; when the working object distance is 350 mm, the air gap between the ninth lens B-9 and the tenth lens B-10 is 2.835 mm; and when the working object distance is infinity, the air gap between the ninth lens B-9 and the tenth lens B-10 is 0.418 mm.

[0032] In the embodiment, the optical system focal length of the lens is f, and the system focal lengths of the first lens A-1, the second lens A-2, the third lens A-3, the fourth lens A-4, the fifth lens A-5, the sixth lens A-6, the seventh lens A-7, the eighth lens B-8, the ninth lens B-9, the tenth lens B-10, the eleventh lens B-11, and the twelfth lens B-12 are f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, and f12, respectively. The optical system focal length f of the lens satisfies the following conditions: -81 mm < f1 < -80 mm; 42 mm < f2 < 43 mm; f3 = -85.185 mm; f4 = 30.128 mm; -27 mm < f5 < -26 mm; f6 = -21.449 mm; f7 = 22.179 mm; f8 = -28.498 mm; f9 = 15.157 mm; f10 = 54.05 mm; f11 = -35.953 mm; and f12 = 76.282 mm.

[0033] In the embodiment, the parameters of each lens are shown in the following table:

[0034]

[0035]

[0036] The technical indicators of the optical system provided in the embodiment are as follows:

[0037] (1) focal length: f = 25mm;

[0038] (2) relative aperture: D / f = 1:2.0;

[0039] (3) field angle: 2w ≥ 35.3°;

[0040] (4) distortion: <0.25%;

[0041] (5) target surface: 1.1" CCD (diagonal 17.6mm);

[0042] (6) resolution: can be matched with 12 million pixel high resolution CCD industrial camera;

[0043] (7) total length of optical path ∑ ≤ 85mm, optical back intercept L' ≥ 13.71mm;

[0044] (8) applicable spectral range: 400nm-700nm.

[0045] In summary, the present application provides a large aperture, large target surface high-definition fixed focus industrial lens, which has the characteristics of high resolution, large aperture, large target surface, compact structure, floating focusing technology, can greatly reduce chromatic aberration from near and far distance, and can obtain good image quality under different working distances, low distortion, and small image distortion.

[0046] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent transformation, direct or indirect application in related technical fields using the content of the present application specification and drawings are also included in the patent protection scope of the present application.

Claims

1. A large aperture, large target surface, high-definition fixed-focus industrial lens, characterized by: The optical system of the lens consists of a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power, a fifth lens with negative focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, an aperture, an eighth lens with negative focal power, a ninth lens with positive focal power, a tenth lens with positive focal power, an eleventh lens with negative focal power, and a twelfth lens with positive focal power, which are arranged in sequence from front to back along the incident light path; The first lens is a meniscus glass spherical lens, the second lens is a biconvex glass spherical lens, the third lens is a meniscus glass spherical lens, the fourth lens is a meniscus glass spherical lens, the fifth lens is a meniscus glass spherical lens, the sixth lens is a biconcave glass spherical lens, the seventh lens is a biconvex glass spherical lens, the eighth lens is a meniscus glass spherical lens, the ninth lens is a biconvex glass spherical lens, the tenth lens is a meniscus glass spherical lens, the eleventh lens is a meniscus glass spherical lens, and the twelfth lens is a meniscus glass spherical lens; the third lens and the fourth lens are cemented to form a first cemented lens, the sixth lens and the seventh lens are cemented to form a second cemented lens, the eighth lens and the ninth lens are cemented to form a third cemented lens, and the tenth lens and the eleventh lens are cemented to form a fourth cemented lens; The air gap between the first lens and the second lens is 17.26 mm, the air gap between the second lens and the third lens is 0.1 mm, the air gap between the fourth lens and the fifth lens is 0.768 mm, the air gap between the fifth lens and the sixth lens is 1.657 mm, the air gap between the seventh lens and the eighth lens is 4 mm, the air gap between the ninth lens and the tenth lens is adjustable, and the air gap between the eleventh lens and the twelfth lens is 0.878 mm.

2. The large aperture, large target surface, high-definition fixed-focus industrial lens according to claim 1, characterized in that: When the working object distance changes, the lens focuses by adjusting the air gap between the ninth lens and the tenth lens. When the working object distance is 200 mm, the air gap between the ninth lens and the tenth lens is 4.6 mm; when the working object distance is 350 mm, the air gap between the ninth lens and the tenth lens is 2.835 mm; when the working object distance is infinity, the air gap between the ninth lens and the tenth lens is 0.418 mm.

3. The large aperture, large target surface, high-definition fixed-focus industrial lens according to claim 1, characterized in that: Assume that the focal length of the optical system of the lens is f, and the system focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, and the twelfth lens are f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, and f12 respectively. The optical system focal length f of the lens satisfies the following conditions: -81mm <f1<-80mm;42mm<f2<43mm;f3=-85.185mm;f4=30.128mm;-27mm<f5<-26mm;f6=-21.449mm;f7=22.179mm;f8=-28.498mm;f9=15.157mm;f10=54.05mm;f11=-35.953mm;f12=76.282mm。

Images