CN117950173A

CN117950173A - Industrial lens

Info

Publication number: CN117950173A
Application number: CN202311848266.7A
Authority: CN
Inventors: 黄健新; 高博; 李伟娜; 何晓源; 赖晗
Original assignee: Zhongshan Liantuo Optical Co ltd
Current assignee: Zhongshan Liantuo Optical Co ltd
Priority date: 2023-12-29
Filing date: 2023-12-29
Publication date: 2024-04-30

Abstract

The invention discloses an industrial lens, the number of lens groups with optical power is 2, and the lens groups sequentially comprise from an object side to an imaging surface along an optical axis: a first lens group having negative optical power; a second lens group having positive optical power; during focusing, the first lens group moves in the optical axis direction relative to the second lens group, and the second lens group moves in the optical axis direction relative to the imaging surface. The industrial lens provided by the invention can improve the imaging quality of the industrial lens by controlling the focal length ratio of the first lens group to the industrial lens and the focal length ratio of the first lens group to the second lens group, when focusing is carried out on different object distances, the first lens group moves relative to the second lens group in the optical axis direction, the second lens group moves in the optical axis direction relative to the imaging surface, so that the industrial lens can be imaged clearly in a wide working distance, the application range of the industrial lens is improved, a 4/3' inch chip can be adapted, and the imaging lens has the advantages of large target surface, low distortion and high resolution.

Description

Industrial lens

Technical Field

The invention relates to the technical field of imaging lenses, in particular to an industrial lens.

Background

An industrial lens is an optical lens specially used in an industrial environment, and is mainly used for capturing and analyzing images in the fields of machine vision, process control and automation, in other words, the industrial lens can be used as an eye of a machine, all image information processed by an industrial system is obtained through the lens, and the quality of the lens can directly influence the overall performance of a vision system.

Industrial lenses are generally more complex in design than conventional optical lenses, which are required to meet higher requirements. With the rapid development of industrial automation, the demand for industrial lenses is also increasing. The existing industrial lens has the defects of different degrees in terms of image plane size, distortion, picture quality and working distance, so that the industrial lens with larger target surface, smaller distortion, higher resolution and wider working distance is increasingly demanded.

Disclosure of Invention

Based on the above, the invention aims to provide an industrial lens which has at least the advantages of large target surface, low distortion, high resolving power and wide working distance.

The invention provides an industrial lens, the number of lens groups with optical power is 2, and the industrial lens sequentially comprises from an object side to an imaging surface along an optical axis: a first lens group having negative optical power and a second lens group having positive optical power; during focusing, the first lens group moves in the optical axis direction relative to the second lens group, the second lens group moves in the optical axis direction relative to the imaging surface, and the industrial lens satisfies the following conditional expression: -3.0< f _Q1/f<-1.6;-2.3<f_Q1/f_Q2 < -1.2; wherein f _Q1 denotes an effective focal length of the first lens group, f _Q2 denotes an effective focal length of the second lens group, and f denotes an effective focal length of the industrial lens.

The industrial lens provided by the invention can improve the imaging quality of the industrial lens by controlling the focal length ratio of the first lens group to the industrial lens and the focal length ratio of the first lens group to the second lens group, when focusing is carried out on different object distances, the first lens group moves relative to the second lens group in the optical axis direction, the second lens group moves in the optical axis direction relative to the imaging surface, so that the industrial lens can be imaged clearly in a wide working distance, the application range of the industrial lens is improved, a 4/3' inch chip can be adapted, and the imaging lens has the advantages of large target surface, low distortion and high resolution.

Drawings

Fig. 1 is a schematic structural diagram of an industrial lens according to a first embodiment of the present invention;

FIG. 2 is a graph of F-Tanθ distortion of an industrial lens at an object distance of 800mm in a first embodiment of the present invention;

FIG. 3 is a graph showing the MTF of an industrial lens at an object distance of 800mm according to a first embodiment of the present invention;

FIG. 4 is a graph showing F-Tanθ distortion of an industrial lens at an object distance of 1200mm according to a first embodiment of the present invention;

FIG. 5 is a graph showing the MTF of an industrial lens at an object distance of 1200mm according to the first embodiment of the present invention;

FIG. 6 is a graph of F-Tanθ distortion of an industrial lens at an object distance of 200mm in a first embodiment of the present invention;

FIG. 7 is a graph showing the MTF of an industrial lens at an object distance of 200mm according to the first embodiment of the present invention;

fig. 8 is a schematic structural diagram of an industrial lens according to a second embodiment of the present invention;

FIG. 9 is a graph of F-Tanθ distortion of an industrial lens at an object distance of 800mm according to a second embodiment of the present invention;

FIG. 10 is a graph showing the MTF of an industrial lens at an object distance of 800mm according to a second embodiment of the present invention;

FIG. 11 is a graph of F-Tanθ distortion of an industrial lens at an object distance of 1200mm according to a second embodiment of the present invention;

FIG. 12 is a graph showing the MTF of an industrial lens at an object distance of 1200mm according to a second embodiment of the present invention;

FIG. 13 is a graph of F-Tanθ distortion of an industrial lens at an object distance of 200mm according to a second embodiment of the present invention;

FIG. 14 is a graph showing the MTF of an industrial lens at an object distance of 200mm according to a second embodiment of the present invention;

Fig. 15 is a schematic structural diagram of an industrial lens according to a third embodiment of the present invention;

FIG. 16 is a graph of F-Tanθ distortion of an industrial lens at an object distance of 800mm according to a third embodiment of the present invention;

FIG. 17 is a graph showing the MTF of an industrial lens at an object distance of 800mm according to a third embodiment of the present invention;

FIG. 18 is a graph of F-Tanθ distortion of an industrial lens at an object distance of 1200mm according to a third embodiment of the present invention;

FIG. 19 is a graph showing the MTF of an industrial lens at an object distance of 1200mm according to a third embodiment of the present invention;

FIG. 20 is a graph of F-Tanθ distortion of an industrial lens at an object distance of 200mm according to a third embodiment of the present invention;

Fig. 21 is a graph showing MTF curves for an industrial lens at an object distance of 200mm in a third embodiment of the present invention.

Detailed Description

In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Like reference numerals refer to like elements throughout the specification.

The invention provides an industrial lens, the number of lens groups with optical power is 2, and the industrial lens sequentially comprises from an object side to an imaging surface along an optical axis: a first lens group having negative optical power, a second lens group having positive optical power; during focusing, the first lens group moves in the optical axis direction relative to the second lens group, and the second lens group moves in the optical axis direction relative to the imaging surface. The industrial lens satisfies the following conditional expression:

-3.0<f_Q1/f<-1.6；

-2.3<f_Q1/f_Q2<-1.2；

Wherein f _Q1 denotes an effective focal length of the first lens group, f _Q2 denotes an effective focal length of the second lens group, and f denotes an effective focal length of the industrial lens.

Compared with the prior art, the industrial lens provided by the invention has the advantages that the imaging quality of the industrial lens can be improved by controlling the focal length ratio of the first lens group to the industrial lens and the focal length ratio of the first lens group to the second lens group, when focusing is conducted on different object distances, the first lens group moves relative to the second lens group in the optical axis direction, the second lens group moves relative to the imaging surface in the optical axis direction, the industrial lens can be imaged clearly in a wide working distance, the application range of the industrial lens is improved, a 4/3' inch chip can be adapted, and the industrial lens has the advantages of large target surface, low distortion and high resolving power.

Further, when the industrial lens aims at different object distances, the second lens group can be kept motionless, the first lens group is moved, after the positions of the first lens group and the second lens group are adjusted in place, the first lens group and the second lens group are moved at the same time, and focusing is realized after the positions of the second lens group and the imaging surface are adjusted in place. Or the first lens group is kept still, the second lens group is moved, after the positions of the first lens group and the imaging surface are adjusted to be in place, the first lens group is moved, and focusing is realized after the positions of the first lens group and the second lens group are adjusted to be in place. Or dynamically moving the first lens group and the second lens group to adjust the positions of the first lens group and the second lens group and the positions of the second lens group and the imaging surface to be in place so as to realize focusing. The above-mentioned adjustment methods are only listed, and the specific moving modes of the first lens group and the second lens group can be selected according to the lens barrel structure, and the present invention is not limited thereto, as long as the distance between the first lens group and the second lens group and the distance between the second lens group and the imaging surface can be adjusted.

In some embodiments, the industrial lens further comprises a stop. Preferably, the diaphragm is an iris diaphragm. The iris diaphragm is used for limiting the light entering quantity under different object distances and different environments so as to change the brightness of imaging and improve the imaging performance and quality of the industrial lens. Preferably, the iris is located between the first lens group and the second lens group, so that the functions of the first lens group and the second lens group can be reasonably distributed, for example, the first lens group receives light rays with a large angle of view, so that the lens has a larger angle of view, the second lens group corrects aberration, and the structure of the industrial lens is simplified to improve imaging quality. Preferably, during focusing, the iris diaphragm can synchronously move with the second lens group in the optical axis direction, so that the requirements of the industrial lens under different object distances can be better met.

In some embodiments, the industrial lens further comprises a filter, wherein the filter comprises an object side surface and an image side surface. The optical filter can be an infrared cut-off optical filter and is used for filtering interference light and preventing the interference light from reaching an imaging surface of the industrial lens to influence normal imaging. Preferably, the optical filter is located between the second lens group and the imaging surface, so that imaging quality of the industrial lens can be improved. Preferably, during focusing, the optical filter can synchronously move with the second lens group in the optical axis direction, so that the requirements of the industrial lens under different object distances can be better met.

In some embodiments, the industrial lens adjusts the distance between the first lens group and the second lens group and the distance between the second lens group and the imaging surface for different object distances, so that the imaging picture is clear; the aperture of the iris diaphragm is adjusted according to the environment illumination condition to adjust the light quantity, so that the industrial lens achieves the optimal imaging picture to improve the imaging quality.

In some embodiments, the industrial lens satisfies the following conditional expression:

-38<f×IH/f_Q1<-19；

Wherein IH represents the real image height corresponding to the maximum field angle of the industrial lens, f represents the effective focal length of the industrial lens, and f _Q1 represents the effective focal length of the first lens group. The above conditional expression is satisfied, and the value of f multiplied by IH/f _Q1 is reasonably controlled, so that the larger effective focal length can be obtained, the larger imaging area can be obtained, and the method is suitable for chips with higher pixels.

40<f×IH/f_Q2<51；

Wherein IH represents the real image height corresponding to the maximum field angle of the industrial lens, f represents the effective focal length of the industrial lens, and f _Q2 represents the effective focal length of the second lens group. The above conditional expression is satisfied, and the value of f multiplied by IH/f _Q2 is reasonably controlled, so that the larger effective focal length can be obtained, the larger imaging area can be obtained, and the method is suitable for chips with higher pixels.

1.6<IH/FNO<7.5；

Wherein IH represents the real image height corresponding to the maximum field angle of the industrial lens, and FNO represents the aperture value of the industrial lens. The lens has the balance characteristics of a large image plane and a large aperture, the luminous flux entering the lens can be increased, the influence of insufficient light on an imaging picture is reduced, the lens has good imaging effect under a scene with insufficient illumination, and the imaging requirements of different bright and dark environments are met.

1.15<f_Q2/f<1.45；

Wherein f _Q2 denotes an effective focal length of the second lens group, and f denotes an effective focal length of the industrial lens. The image plane size of the industrial lens can be improved by controlling the focal length ratio of the second lens group to the industrial lens so that the industrial lens has the characteristic of a large target surface.

2.4<TTL/IH<3.1；

Wherein TTL represents the total optical length of the industrial lens, and IH represents the real image height corresponding to the maximum field angle of the industrial lens. The large target surface imaging of the industrial lens can be realized by meeting the above conditional expression, the pixel point size can be improved under the same pixel size, and the receiving efficiency of the chip to light can be improved, so that high-pixel imaging is realized, and the imaging picture quality is improved.

5.1<TTL/f<6.3；

Where TTL represents the total optical length of the industrial lens and f represents the effective focal length of the industrial lens. The above conditional expression is satisfied, enough space can be provided in the lens, so that the first lens group and the second lens group can move in the optical axis direction conveniently, and accurate focusing can be realized at different object distances.

In some embodiments, the first lens group includes, in order from an object side to an imaging surface along the optical axis: a first lens having positive optical power, a second lens having negative optical power, a third lens having negative optical power, a fourth lens having positive optical power, a fifth lens having negative optical power, and a sixth lens having positive optical power. Through reasonable focal power distribution, the lens has the characteristics of large field angle, small distortion and high pixel imaging while being compact in structure, and the requirements of industrial lenses are better met.

Preferably, the object side surface of the first lens is a convex surface, and the image side surface is a concave surface; the object side surface of the second lens is a convex surface, and the image side surface is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface is a concave surface; the object side surface and the image side surface of the fourth lens are convex; the object side surface of the fifth lens is a convex surface, and the image side surface is a concave surface; the sixth lens element has a convex object-side surface and a concave image-side surface. The imaging quality of the industrial lens can be further improved through specific surface shape collocation.

In some implementations, the industrial lens satisfies one or more of the following conditional expressions:

5.7<f₁/f<7.5；

-1.6<f₂/f<-1.2；

-1.5<f₃/f<-1.1；

2.3<f₄/f<3.6；

-1.6<f₅/f<-0.9；

0.7<f₆/f<1.2；

Wherein f ₁ denotes an effective focal length of the first lens, f ₂ denotes an effective focal length of the second lens, f ₃ denotes an effective focal length of the third lens, f ₄ denotes an effective focal length of the fourth lens, f ₅ denotes an effective focal length of the fifth lens, f ₆ denotes an effective focal length of the sixth lens, and f denotes an effective focal length of the industrial lens. The first lens has proper positive focal power, can effectively collect light rays and can compress the total optical length of the industrial lens; the second lens has proper negative focal power, which is favorable for balancing various aberrations of the industrial lens and improving imaging quality; the third lens has proper negative focal power, is favorable for balancing various chromatic aberration of the industrial lens, and improves imaging quality; the fourth lens has proper positive focal power, which is beneficial to increasing the imaging area of the industrial lens and improving the imaging quality of the industrial lens; the fifth lens has proper negative focal power, is favorable for balancing the astigmatism of the industrial lens and improves the imaging quality; the sixth lens has proper positive focal power, reduces the deflection angle of light rays when converging the light rays, enables the light rays to stably transition, balances various aberrations of the industrial lens and improves the imaging quality of the industrial lens. One or more of the above conditional expressions are satisfied, so that distortion of the industrial lens can be reduced, and imaging quality of the industrial lens can be improved.

In some embodiments, the industrial lens satisfies the following conditional expression: -4.1< f ₁/f_Q1 < -1.9; where f ₁ denotes an effective focal length of the first lens, and f _Q1 denotes an effective focal length of the first lens group. The first lens has proper focal power ratio, can collect light, and is beneficial to miniaturization.

In some embodiments, the industrial lens satisfies the following conditional expression: 0.45< f ₂/f_Q1 <0.85; where f ₂ denotes an effective focal length of the second lens, and f _Q1 denotes an effective focal length of the first lens group. The second lens has proper focal power ratio, so that the trend of the front light can be gentle and the resolution can be improved.

In some embodiments, the industrial lens satisfies the following conditional expression: 0.4< f ₃/f_Q1 <0.85; where f ₃ denotes an effective focal length of the third lens, and f _Q1 denotes an effective focal length of the first lens group. The third lens has proper focal power ratio, which is helpful for balancing various aberrations of industrial lens.

In some embodiments, the industrial lens satisfies the following conditional expression: -1.8< f ₄/f_Q1 < -0.8; where f ₄ denotes an effective focal length of the fourth lens, and f _Q1 denotes an effective focal length of the first lens group. The above conditional expression is satisfied, so that the fourth lens has proper focal power ratio, light is further converged to reduce the rear end diameter of the industrial lens, and miniaturization is facilitated.

In some embodiments, the industrial lens satisfies the following conditional expression: 0.3< f ₅/f_Q1 <0.85; where f ₅ denotes an effective focal length of the fifth lens, and f _Q1 denotes an effective focal length of the first lens group. The fifth lens can have proper focal power ratio to reduce the sensitivity of the industrial lens by satisfying the above conditional expression.

In some embodiments, the industrial lens satisfies the following conditional expression: -0.65< f ₆/f_Q1 < -0.25; where f ₆ denotes an effective focal length of the sixth lens, and f _Q1 denotes an effective focal length of the first lens group. The above conditional expression is satisfied, so that the sixth lens has a proper focal power ratio, which is favorable for light to smoothly enter the rear optical system.

In some embodiments, the fifth lens and the sixth lens comprise cemented lenses having positive optical powers. The chromatic aberration correction of the industrial lens is shared, the resolution of the industrial lens is improved, the structure of the industrial lens is compact, and the industrial lens is miniaturized.

In some embodiments, the industrial lens satisfies the following conditional expression: 4.5< f ₅₆/f <7.3; wherein f ₅₆ denotes a combined focal length of the fifth lens and the sixth lens, and f denotes an effective focal length of the industrial lens. The lens meets the above conditional expression, is beneficial to controlling the light beam trend between the fifth lens and the sixth lens, is beneficial to mutual correction of aberration, and simultaneously has compact structure and is beneficial to miniaturization.

In some embodiments, the industrial lens satisfies the following conditional expression: -4.1< f ₅₆/f_Q1 < -1.8; where f ₅₆ denotes a combined focal length of the fifth lens and the sixth lens, and f _Q1 denotes an effective focal length of the first lens group. The optical power of the fifth lens and the sixth lens can be optimized by meeting the above conditional expression, which is beneficial to improving the imaging quality.

In some embodiments, the second lens group includes, in order from an object side to an imaging surface along the optical axis: a seventh lens having positive optical power, an eighth lens having positive optical power, a ninth lens having negative optical power, a tenth lens having positive optical power, an eleventh lens having negative optical power, a twelfth lens having positive optical power, and a thirteenth lens having negative optical power. Through reasonable focal power distribution, the lens has the characteristics of large field angle, small distortion and high pixel imaging while being compact in structure, and the requirements of industrial lenses are better met.

Preferably, the image side surface of the seventh lens is convex; the object side surface and the image side surface of the eighth lens are both convex surfaces; the object side surface and the image side surface of the ninth lens are concave surfaces; the object side surface and the image side surface of the tenth lens are both convex surfaces; the object side surface and the image side surface of the eleventh lens are concave surfaces; the object side surface of the twelfth lens is a concave surface, and the image side surface is a convex surface; the thirteenth lens element has a concave object-side surface and a convex image-side surface. The imaging quality of the industrial lens can be further improved through specific surface shape collocation.

1.2<f₇/f<1.8；

0.45<f₈/f<0.95；

-0.65<f₉/f<-0.45；

0.9<f₁₀/f<1.3；

-1.1<f₁₁/f<-0.8；

0.9<f₁₂/f<1.25；

-1.7<f₁₃/f<-1.1；

Wherein f ₇ denotes an effective focal length of the seventh lens, f ₈ denotes an effective focal length of the eighth lens, f ₉ denotes an effective focal length of the ninth lens, f ₁₀ denotes an effective focal length of the tenth lens, f ₁₁ denotes an effective focal length of the eleventh lens, f ₁₂ denotes an effective focal length of the twelfth lens, f ₁₃ denotes an effective focal length of the thirteenth lens, and f denotes an effective focal length of the industrial lens. The seventh lens has proper positive focal power to effectively collect the light rays at the front end of the industrial lens when the conditional expression is satisfied; the eighth lens can have proper positive focal power, and further converge light rays at the front end of the industrial lens; the ninth lens can have proper negative focal power, so that the decentering sensitivity of the industrial lens is reduced; the tenth lens has proper positive focal power, and the light deflection angle is reduced; the eleventh lens can have proper negative focal power and balance various aberrations generated by the front lens; the twelfth lens has proper positive focal power, balances various aberrations of the industrial lens and improves imaging quality; the thirteenth lens can be made to have a proper negative power, increasing the imaging area of the industrial lens. One or more of the above conditional expressions are satisfied, so that distortion of the industrial lens can be reduced, and imaging quality of the industrial lens can be improved.

In some embodiments, the industrial lens satisfies the following conditional expression: 1<f ₇/f_Q2 <1.3; where f ₇ denotes an effective focal length of the seventh lens, and f _Q2 denotes an effective focal length of the second lens group. The seventh lens can have proper positive focal power, so that the light rays at the front end of the industrial lens can be effectively converged.

In some embodiments, the industrial lens satisfies the following conditional expression: 0.35< f ₈/f_Q2 <0.7; wherein f ₈ denotes an effective focal length of the eighth lens, and f _Q2 denotes an effective focal length of the second lens group. The eighth lens can have proper positive focal power to further converge the light rays at the front end of the industrial lens by meeting the above conditional expression.

In some embodiments, the industrial lens satisfies the following conditional expression: -0.55< f ₉/f_Q2 < -0.3; where f ₉ denotes an effective focal length of the ninth lens, and f _Q2 denotes an effective focal length of the second lens group. The ninth lens has proper negative focal power and reduces the decentering sensitivity of the industrial lens by meeting the above conditional expression.

In some embodiments, the industrial lens satisfies the following conditional expression: 0.65< f ₁₀/f_Q2 <1.05; where f ₁₀ denotes an effective focal length of the tenth lens, and f _Q2 denotes an effective focal length of the second lens group. The tenth lens has proper positive focal power and reduces the light deflection angle by satisfying the above conditional expression.

In some embodiments, the industrial lens satisfies the following conditional expression: -0.85< f ₁₁/f_Q2 < -0.6; where f ₁₁ denotes an effective focal length of the eleventh lens, and f _Q2 denotes an effective focal length of the second lens group. The above conditional expression is satisfied, so that the eleventh lens has appropriate negative focal power and balances various aberrations generated by the front lens.

In some embodiments, the industrial lens satisfies the following conditional expression: 0.7< f ₁₂/f_Q2 <0.9; where f ₁₂ denotes an effective focal length of the twelfth lens, and f _Q2 denotes an effective focal length of the second lens group. The twelfth lens has proper positive focal power, balances various aberrations of the industrial lens and improves imaging quality by meeting the conditional expression.

In some embodiments, the industrial lens satisfies the following conditional expression: -1.3< f ₁₃/f_Q2 < -0.7; where f ₁₃ denotes an effective focal length of the thirteenth lens, and f _Q2 denotes an effective focal length of the second lens group. The thirteenth lens can have proper negative focal power to increase the imaging area of the industrial lens by satisfying the above conditional expression.

In some embodiments, the eighth lens and the ninth lens form a cemented lens. The chromatic aberration correction of the industrial lens is shared, the resolution of the industrial lens is improved, the structure of the industrial lens is compact, and the industrial lens is miniaturized.

In some embodiments, the tenth lens and the eleventh lens comprise cemented lenses having negative optical power. The chromatic aberration correction of the industrial lens is shared, the resolution of the industrial lens is improved, the structure of the industrial lens is compact, and the industrial lens is miniaturized.

In some embodiments, the twelfth lens and the thirteenth lens form a cemented lens with positive optical power. The chromatic aberration correction of the industrial lens is shared, the resolution of the industrial lens is improved, the structure of the industrial lens is compact, and the industrial lens is miniaturized.

In some embodiments, the industrial lens satisfies the following conditional expression: 10< |f ₈₉/f| <18; wherein f ₈₉ denotes a combined focal length of the eighth lens and the ninth lens, and f denotes an effective focal length of the industrial lens. The lens meets the above conditional expression, is favorable for controlling the light beam trend between the eighth lens and the ninth lens, is favorable for mutual correction of aberration, and simultaneously has compact structure and is favorable for miniaturization.

In some embodiments, the industrial lens satisfies the following conditional expression: -19< f ₁₀₁₁/f < -7.5; where f ₁₀₁₁ denotes a combined focal length of the tenth lens and the eleventh lens, and f denotes an effective focal length of the industrial lens. The lens meets the above conditional expression, is conducive to control of the light ray trend between the tenth lens and the eleventh lens, is conducive to mutual correction of aberration, and is also conducive to miniaturization.

In some embodiments, the industrial lens satisfies the following conditional expression: 4<f ₁₂₁₃/f <8.6; where f ₁₂₁₃ denotes a combined focal length of the twelfth lens and the thirteenth lens, and f denotes an effective focal length of the industrial lens. The lens meets the above conditional expression, is favorable for controlling the light beam trend between the twelfth lens and the thirteenth lens, is favorable for mutual correction of aberration, and simultaneously has compact structure and is favorable for miniaturization.

In some embodiments, the industrial lens satisfies the following conditional expression: 8< |f ₈₉/f_Q2 | <13; where f ₈₉ denotes a combined focal length of the eighth lens and the ninth lens, and f _Q2 denotes an effective focal length of the second lens group. The optical power of the eighth lens and the ninth lens can be optimized by meeting the above conditional expression, which is beneficial to improving the imaging quality.

In some embodiments, the industrial lens satisfies the following conditional expression: -14< f ₁₀₁₁/f_Q2 < -6; where f ₁₀₁₁ denotes a combined focal length of the tenth lens and the eleventh lens, and f _Q2 denotes an effective focal length of the second lens group. The optical power of the tenth lens and the eleventh lens can be optimized by satisfying the above conditional expression, which is favorable for improving imaging quality.

In some embodiments, the industrial lens satisfies the following conditional expression: 2.9< f ₁₂₁₃/f_Q2 <6.3; where f ₁₂₁₃ denotes a combined focal length of the twelfth lens and the thirteenth lens, and f _Q2 denotes an effective focal length of the second lens group. The optical powers of the twelfth lens and the thirteenth lens can be optimized to satisfy the above conditional expression, which is advantageous for improving imaging quality.

In some embodiments, the first lens to the thirteenth lens are each glass spherical lenses. The offset of the back focus of the industrial lens along with the temperature change can be effectively restrained, so that the temperature stability of the industrial lens is improved, and the imaging capability of the industrial lens can be further improved.

In some embodiments, the industrial lens satisfies the following conditional expression: 0.01< beta <0.15; wherein, beta represents the corresponding magnification of the industrial lens at different object distances. The above conditional expression is satisfied, so that the industrial lens has a certain range of magnification, the application range of the industrial lens is improved, and the industrial lens can be normally used under different object distances. Preferably, 0.02< β <0.12.β=ih/D3, D3 represents the maximum object plane size corresponding to the industrial lens at different object distances, IH represents the real image height corresponding to the industrial lens at the maximum field angle, and β represents the magnification corresponding to the industrial lens at different object distances.

In some embodiments, the industrial lens satisfies the following conditional expression: 24< D0/D4<240; wherein D0 represents an object distance, that is, a distance between an object plane and a first lens of the industrial lens in the optical axis direction, and D4 represents a distance between the first lens group and the second lens group in the optical axis direction. The distance between the first lens group and the object plane can be ensured to be in a proper working range by meeting the conditional expression, and the imaging quality of the industrial lens is improved.

In some embodiments, the industrial lens satisfies the following conditional expression: 10< D0/D5<105; wherein D0 represents an object distance, that is, a distance between an object plane and a first lens of the industrial lens in the optical axis direction, and D5 represents a distance between the second lens group and the imaging plane in the optical axis direction. The distance between the second lens group and the imaging surface can be ensured to be in a proper working range by meeting the conditional expression, and the imaging quality of the industrial lens is improved.

In some embodiments, the industrial lens satisfies the following conditional expression: 0.2< D4/D5<0.65; wherein D4 is a distance between the first lens group and the second lens group in the optical axis direction; d5 is a distance between the second lens group and the imaging surface in the optical axis direction. The distance between the first lens group and the second lens group can be ensured to be in a proper working range by meeting the conditional expression, and the imaging quality of the industrial lens is improved.

In some embodiments, the industrial lens satisfies the following conditional expression: 80 ° < FOV <100 °,4< fno <16; where FOV represents the maximum field angle of the industrial lens, and FNO represents the aperture value of the industrial lens. The above conditional expression is satisfied, the application range of the industrial lens can be improved, the industrial lens has the characteristic of large field of view, and good imaging can be realized in different illumination environments.

The invention is further illustrated in the following examples. In various embodiments, the thickness, radius of curvature, and material selection portion of each lens in an industrial lens may vary, and for specific differences, reference may be made to the parameter tables of the various embodiments. The following examples are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and any other changes, substitutions, combinations or simplifications that do not depart from the gist of the present invention are intended to be equivalent substitutes within the scope of the present invention.

First embodiment

Referring to fig. 1, a schematic structural diagram of an industrial lens 100 according to a first embodiment of the present invention is shown, where the industrial lens 100 includes, in order from an object side to an imaging surface S27 along an optical axis: a first lens group Q1, a stop ST, a second lens group Q2, an optical filter G1, and a protective glass G2; the first lens group Q1 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6, and the second lens group Q2 includes a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, a twelfth lens L12, and a thirteenth lens L13.

The first lens element L1 has positive refractive power, wherein an object-side surface S1 thereof is convex, and an image-side surface S2 thereof is concave; the second lens element L2 has negative refractive power, wherein an object-side surface S3 thereof is convex, and an image-side surface S4 thereof is concave; the third lens element L3 has negative refractive power, wherein an object-side surface S5 thereof is convex, and an image-side surface S6 thereof is concave; the fourth lens element L4 has positive refractive power, and both an object-side surface S7 and an image-side surface S8 thereof are convex; the fifth lens element L5 has a negative refractive power, wherein an object-side surface S9 thereof is convex, an image-side surface thereof is concave, the sixth lens element L6 has a positive refractive power, an object-side surface thereof is convex, an image-side surface S11 thereof is concave, the fifth lens element L5 and the sixth lens element L6 form a cemented lens with positive refractive power, and the image-side surface of the fifth lens element L5 and the object-side surface of the sixth lens element form a cemented lens with positive refractive power S10; the seventh lens L7 has positive focal power, and both an object side surface S12 and an image side surface S13 of the seventh lens L have convex surfaces; the eighth lens element L8 has positive refractive power, wherein the object-side surface S14 and the image-side surface thereof are convex, the ninth lens element L9 has negative refractive power, the object-side surface and the image-side surface S16 thereof are concave, the eighth lens element L8 and the ninth lens element L9 form a cemented lens with negative refractive power, and the image-side surface of the eighth lens element L8 and the object-side surface of the ninth lens element L9 form a cemented lens element S15; the tenth lens L10 has positive refractive power, the object side surface S17 and the image side surface thereof are both convex, the eleventh lens L11 has negative refractive power, the object side surface and the image side surface S19 thereof are both concave, the tenth lens L10 and the eleventh lens L11 form a cemented lens with negative refractive power, and the image side surface of the tenth lens L10 and the object side surface of the eleventh lens L11 form a cemented surface S18; the twelfth lens element L12 with positive refractive power has a concave object-side surface S20 and a convex image-side surface, the thirteenth lens element L13 with negative refractive power has a concave object-side surface S22 and a convex image-side surface S22, the twelfth lens element L12 and the thirteenth lens element L13 form a cemented lens with positive refractive power, and the image-side surface of the twelfth lens element L12 and the object-side surface of the thirteenth lens element L13 form a cemented lens with positive refractive power S21; the object side surface of the optical filter G1 is S23, and the image side surface is S24; the object side surface of the cover glass G2 is S25, and the image side surface is S26.

In this embodiment, the first lens to the thirteenth lens are glass spherical lenses. The offset of the back focus of the industrial lens along with the temperature change can be effectively restrained, so that the temperature stability of the industrial lens is improved, and the imaging capability of the industrial lens can be further improved.

The relevant parameters of each lens in the industrial lens 100 according to the first embodiment of the present invention are shown in table 1.

TABLE 1

The relevant parameters of the industrial lens 100 after focusing at different object distances according to the first embodiment of the present invention are shown in table 2.

TABLE 2

D0(mm)	D1(mm)	D2(mm)	TTL(mm)	D3(mm)	IH(mm)	β
							800	3.34	9.91	164.74	1776	60	0.03
1200	3.50	9.58	164.57	2626	60	0.02
							200	2.22	12.60	166.32	499	60	0.12

Wherein D0 is an object distance, that is, a distance between the object plane and the object side surface S1 of the first lens element L1 in the optical axis direction, D1 is a distance between the image side surface S11 of the sixth lens element L6 and the stop ST in the optical axis direction, D2 is a distance between the image side surface S24 of the filter G1 and the object side surface S25 of the cover glass G2 in the optical axis direction, and TTL is an optical total length of the industrial lens 100. D3 is the maximum object plane size corresponding to the industrial lens 100 at different object distances, IH is the real image height corresponding to the industrial lens 100 at the maximum field angle, β is the magnification corresponding to the industrial lens 100 at different object distances, and β=ih/D3.

In this embodiment, the schematic structure of the industrial lens 100, the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 800mm, the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 1200mm, and the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 200mm are shown in fig. 1 to 7, respectively. The structure of the industrial lens 100 in fig. 1 corresponds to the dimensions of D0, D1 and D2 being adaptively adjusted when the object distance is 800mm, 1200mm and 200 mm. It should be understood that the above-mentioned specific examples of the industrial lens 100 at several different object distances are listed, and the industrial lens 100 according to the present embodiment can clearly image in the range of 200mm to 1200 mm.

Fig. 2 shows an optical F-Tan θ distortion graph of the industrial lens 100 of the present embodiment at an object distance of 800mm, which represents distortion at different image heights on an imaging plane, in which the horizontal axis represents the percent distortion and the vertical axis represents the half image height (unit: mm). From the figure, it can be seen that the optical distortion is controlled within ±2%, indicating that the distortion of the industrial lens 100 is well corrected.

Fig. 3 shows an MTF (modulation transfer function) graph of the industrial lens 100 of the present embodiment at an object distance of 800mm, which represents lens imaging modulation degrees of different spatial frequencies at respective fields of view, the horizontal axis representing spatial frequencies (units: lp/mm), and the vertical axis representing MTF values. As can be seen from the graph, the MTF value is over 0.35 in the whole field of view, and in the range of 0-45 lp/mm, the MTF curve is uniformly and smoothly reduced, and the imaging quality and the detail resolving power are good under the conditions of low frequency and high frequency.

Fig. 4 shows an optical F-Tan θ distortion graph of the industrial lens 100 of the present embodiment at an object distance of 1200mm, which represents distortion at different image heights on an imaging plane, in which the horizontal axis represents the percent distortion and the vertical axis represents the half image height (unit: mm). From the figure, it can be seen that the optical distortion is controlled within ±2%, indicating that the distortion of the industrial lens 100 is well corrected.

Fig. 5 shows an MTF (modulation transfer function) graph of the industrial lens 100 of the present embodiment at an object distance of 1200mm, which represents the lens imaging modulation degrees of different spatial frequencies at each view field, the horizontal axis represents the spatial frequency (unit: lp/mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF value is over 0.3 in the whole field of view, and in the range of 0-45 lp/mm, the MTF curve is uniformly and smoothly reduced, and the imaging quality and the detail resolving power are good under the conditions of low frequency and high frequency.

Fig. 6 shows an optical F-Tan θ distortion graph of the industrial lens 100 of the present embodiment at an object distance of 200mm, which represents distortion at different image heights on an imaging plane, in which the horizontal axis represents the percent distortion and the vertical axis represents the half image height (unit: mm). From the figure, it can be seen that the optical distortion is controlled within ±3%, indicating that the distortion of the industrial lens 100 is well corrected.

Fig. 7 shows an MTF (modulation transfer function) graph of the industrial lens 100 of the present embodiment at an object distance of 200mm, which represents the lens imaging modulation degrees of different spatial frequencies at each view field, the horizontal axis represents the spatial frequency (unit: lp/mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF value is more than 0.4 in the whole field of view, and in the range of 0-22 lp/mm, the MTF curve is uniformly and smoothly reduced, and the imaging quality and the detail resolving power are good under the conditions of low frequency and high frequency.

Second embodiment

The industrial lens 200 according to the second embodiment of the present invention has substantially the same structure as the industrial lens 100 according to the first embodiment, and is different in that the object-side surface S12 of the seventh lens element L7 is a concave surface, the eighth lens element L8 and the ninth lens element L9 form a cemented lens with positive focal power, and the parameters such as the radius of curvature of each lens element are different.

The relevant parameters of each lens in the industrial lens 200 according to the second embodiment of the present invention are shown in table 3.

TABLE 3 Table 3

The relevant parameters of the industrial lens 200 after focusing at different object distances according to the second embodiment of the present invention are shown in table 4.

TABLE 4 Table 4

D0(mm)	D1(mm)	D2(mm)	TTL(mm)	D3(mm)	IH(mm)	β
							800	2.69	11.29	157.27	1772	60	0.03
1200	2.85	10.93	157.07	2616	60	0.02
							200	1.84	13.85	158.97	510	60	0.12

Wherein D0 is an object distance, i.e. a distance between the object plane and the object side surface S1 of the first lens L1 in the optical axis direction; d1 is a distance between the image side surface S11 of the sixth lens L6 and the stop ST in the optical axis direction; d2 is the distance between the image side surface S24 of the optical filter G1 and the object side surface S25 of the cover glass G2 in the optical axis direction; TTL is the total optical length of the industrial lens 200. D3 is the maximum object plane size corresponding to the industrial lens 200 at different object distances, IH is the real image height corresponding to the industrial lens 200 at the maximum field angle, β is the magnification corresponding to the industrial lens 200 at different object distances, and β=ih/D3.

In this embodiment, the schematic structure of the industrial lens 200, the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 800mm, the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 1200mm, and the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 200mm are shown in FIGS. 8 to 14, respectively. The structure of the industrial lens 200 in fig. 8 corresponds to the dimensions of D0, D1 and D2 being adaptively adjusted when the object distance is 800mm, 1200mm and 200 mm. It should be understood that the above-mentioned specific examples of the industrial lens 200 at several different object distances are listed, and the industrial lens 200 according to the present embodiment can clearly image in the range of 200mm to 1200 mm.

As can be seen from fig. 9, when the object distance is 800mm, the F-Tan θ distortion of the industrial lens 200 is controlled within ±2%, which indicates that the distortion of the industrial lens 200 is well corrected; as can be seen from fig. 10, the MTF values are above 0.3 in the full field of view, and in the range of 0-45 lp/mm, the MTF curves are uniformly and smoothly reduced, and the imaging quality and detail resolving power are better under the conditions of low frequency and high frequency.

When the object distance is 1200mm, as can be seen from fig. 11, the F-Tan θ distortion of the industrial lens 200 is controlled within ±2%, which indicates that the distortion of the industrial lens 200 is well corrected; as can be seen from fig. 12, the MTF values are above 0.3 in the full field of view, and in the range of 0-45 lp/mm, the MTF curves drop evenly and smoothly, and have better imaging quality and better detail resolution under both low frequency and high frequency conditions.

When the object distance is 200mm, as can be seen from fig. 13, the F-Tan θ distortion of the industrial lens 200 is controlled within ±3%, which indicates that the distortion of the industrial lens 200 is well corrected; as can be seen from fig. 14, the MTF values are above 0.3 in the full field of view, and in the range of 0-22 lp/mm, the MTF curves are uniformly and smoothly reduced, and the imaging quality and detail resolving power are better under the conditions of low frequency and high frequency.

Third embodiment

The industrial lens 300 according to the third embodiment of the present invention has substantially the same structure as the industrial lens 100 according to the first embodiment, except that parameters such as a radius of curvature of each lens are different.

The relevant parameters of each lens in the industrial lens 300 according to the third embodiment of the present invention are shown in table 5.

TABLE 5

The relevant parameters of the industrial lens 300 after focusing at different object distances according to the third embodiment of the present invention are shown in table 6.

TABLE 6

D0(mm)	D1(mm)	D2(mm)	TTL(mm)	D3(mm)	IH	β
							800	3.36	9.35	166.49	1770	60	0.03
1200	3.53	8.99	166.30	2618	60	0.02
							200	2.31	12.28	168.37	496	60	0.12

Wherein D0 is an object distance, that is, a distance between the object plane and the object side surface S1 of the first lens element L1 in the optical axis direction, D1 is a distance between the image side surface S11 of the sixth lens element L6 and the stop ST in the optical axis direction, D2 is a distance between the image side surface S24 of the filter G1 and the object side surface S25 of the cover glass G2 in the optical axis direction, and TTL is an optical total length of the industrial lens 300. D3 is the maximum object plane size corresponding to the industrial lens 300 at different object distances, IH is the real image height corresponding to the industrial lens 300 at the maximum field angle, β is the magnification corresponding to the industrial lens 200 at different object distances, and β=ih/D3.

In this embodiment, the schematic structure of the industrial lens 300, the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 800mm, the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 1200mm, and the F-Tan θ distortion curve graph and the MTF curve graph at an object distance of 200mm are shown in FIGS. 15 to 21, respectively. The structure of the industrial lens 300 in fig. 15 corresponds to the dimensions of D0, D1 and D2 being adaptively adjusted when the object distance is 800mm, 1200mm and 200 mm. It should be understood that the above-mentioned specific examples of the industrial lens 300 at several different object distances are listed, and the industrial lens 300 according to the present embodiment can clearly image in the range of 200mm to 1200 mm.

When the object distance is 800mm, as can be seen from fig. 16, the F-Tan θ distortion of the industrial lens 300 is controlled within ±2%, which indicates that the distortion of the industrial lens 300 is well corrected; as can be seen from fig. 17, the MTF values are above 0.3 in the full field of view, and in the range of 0-45 lp/mm, the MTF curves drop uniformly and smoothly, and have better imaging quality and better detail resolution under both low frequency and high frequency conditions.

When the object distance is 1200mm, as can be seen from fig. 18, the distortion of the industrial lens 300 is controlled within ±2%, which indicates that the distortion of the industrial lens 300 is well corrected; as can be seen from fig. 19, the MTF values are above 0.3 in the full field of view, and in the range of 0-45 lp/mm, the MTF curves are uniformly and smoothly reduced, and have better imaging quality and better detail resolution under the conditions of low frequency and high frequency.

When the object distance is 200mm, as can be seen from fig. 20, the F-Tan θ distortion of the industrial lens 300 is controlled within ±3%, which indicates that the distortion of the industrial lens 300 is well corrected; as can be seen from fig. 21, the MTF values are above 0.3 in the full field of view, and in the range of 0-22 lp/mm, the MTF curves are uniformly and smoothly reduced, and the imaging quality and detail resolving power are better under the conditions of low frequency and high frequency.

Tables 7 and 8 are optical characteristics corresponding to the three embodiments at different object distances, and mainly include an object distance D0, an effective focal length f, an f-number FNO, an optical total length TTL, a maximum field angle FOV, a corresponding real image height IH, a corresponding magnification β, and values corresponding to the above conditions.

TABLE 7

TABLE 8

In summary, according to the industrial lens provided by the invention, the imaging quality of the industrial lens can be improved by controlling the focal length ratio of the first lens group to the industrial lens and the focal length ratio of the first lens group to the second lens group, when focusing is performed for different object distances, the first lens group moves relative to the second lens group in the optical axis direction, and the second lens group moves relative to the imaging surface in the optical axis direction, so that the industrial lens can be clearly imaged within a wide working distance, the application range of the industrial lens is improved, a 4/3' inch chip can be adapted, and the industrial lens has the advantages of large target surface, low distortion and high resolving power.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above examples represent only a few embodiments of the present invention, which are described in more detail and are not to be construed as limiting the scope of the present invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. The scope of the invention should therefore be pointed out in the appended claims.

Claims

1. An industrial lens, characterized in that the number of lens groups having optical power is 2, comprising, in order from an object side to an imaging surface along an optical axis:

a first lens group having negative optical power;

A second lens group having positive optical power;

during focusing, the first lens group moves in the optical axis direction relative to the second lens group, and the second lens group moves in the optical axis direction relative to the imaging surface;

The industrial lens satisfies the following conditional expression:

-3.0<f_Q1/f<-1.6；

-2.3<f_Q1/f_Q2<-1.2；

2. The industrial lens of claim 1, wherein the industrial lens satisfies the following conditional expression:

-38<f×IH/f_Q1<-19；

Wherein IH represents the real image height corresponding to the maximum field angle of the industrial lens, f represents the effective focal length of the industrial lens, and f _Q1 represents the effective focal length of the first lens group.

3. The industrial lens of claim 1, wherein the industrial lens satisfies the following conditional expression:

40<f×IH/f_Q2<51；

Wherein IH represents the real image height corresponding to the maximum field angle of the industrial lens, f represents the effective focal length of the industrial lens, and f _Q2 represents the effective focal length of the second lens group.

4. The industrial lens of claim 1, wherein the industrial lens satisfies the following conditional expression:

1.6<IH/FNO<7.5；

IH represents the real image height corresponding to the maximum field angle of the industrial lens, and FNO represents the aperture value of the industrial lens.

5. The industrial lens of claim 1, wherein the industrial lens satisfies the following conditional expression:

1.15<f_Q2/f<1.45；

wherein f _Q2 denotes an effective focal length of the second lens group, and f denotes an effective focal length of the industrial lens.

6. The industrial lens of claim 1, wherein the industrial lens satisfies the following conditional expression:

2.4<TTL/IH<3.1；

Wherein TTL represents the total optical length of the industrial lens, and IH represents the real image height corresponding to the maximum field angle of the industrial lens.

7. The industrial lens according to any one of claims 1 to 6, wherein the first lens group includes, in order from an object side to an imaging surface along an optical axis: a first lens having positive optical power, a second lens having negative optical power, a third lens having negative optical power, a fourth lens having positive optical power, a fifth lens having negative optical power, and a sixth lens having positive optical power.

8. The industrial lens of claim 7, wherein the industrial lens satisfies one or more of the following conditional expressions:

5.7<f₁/f<7.5；

-1.6<f₂/f<-1.2；

-1.5<f₃/f<-1.1；

2.3<f₄/f<3.6；

-1.6<f₅/f<-0.9；

0.7<f₆/f<1.2；

Wherein f ₁ denotes an effective focal length of the first lens, f ₂ denotes an effective focal length of the second lens, f ₃ denotes an effective focal length of the third lens, f ₄ denotes an effective focal length of the fourth lens, f ₅ denotes an effective focal length of the fifth lens, f ₆ denotes an effective focal length of the sixth lens, and f denotes an effective focal length of the industrial lens.

9. The industrial lens according to any one of claims 1 to 6, wherein the second lens group includes, in order from an object side to an imaging surface along an optical axis: a seventh lens having positive optical power, an eighth lens having positive optical power, a ninth lens having negative optical power, a tenth lens having positive optical power, an eleventh lens having negative optical power, a twelfth lens having positive optical power, and a thirteenth lens having negative optical power.

10. The industrial lens of claim 9, wherein the industrial lens satisfies one or more of the following conditional expressions:

1.2<f₇/f<1.8；

0.45<f₈/f<0.95；

-0.65<f₉/f<-0.45；

0.9<f₁₀/f<1.3；

-1.1<f₁₁/f<-0.8；

0.9<f₁₂/f<1.25；

-1.7<f₁₃/f<-1.1；

Wherein f ₇ denotes an effective focal length of the seventh lens, f ₈ denotes an effective focal length of the eighth lens, f ₉ denotes an effective focal length of the ninth lens, f ₁₀ denotes an effective focal length of the tenth lens, f ₁₁ denotes an effective focal length of the eleventh lens, f ₁₂ denotes an effective focal length of the twelfth lens, f ₁₃ denotes an effective focal length of the thirteenth lens, and f denotes an effective focal length of the industrial lens.