CN107608051B - Machine vision lens - Google Patents
Machine vision lens Download PDFInfo
- Publication number
- CN107608051B CN107608051B CN201710846357.5A CN201710846357A CN107608051B CN 107608051 B CN107608051 B CN 107608051B CN 201710846357 A CN201710846357 A CN 201710846357A CN 107608051 B CN107608051 B CN 107608051B
- Authority
- CN
- China
- Prior art keywords
- lens
- machine vision
- group
- lens group
- focal length
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000003287 optical effect Effects 0.000 claims abstract description 32
- 239000005308 flint glass Substances 0.000 claims description 8
- 238000003384 imaging method Methods 0.000 claims description 7
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 3
- 239000010436 fluorite Substances 0.000 claims description 3
- 239000011521 glass Substances 0.000 claims description 3
- 239000003292 glue Substances 0.000 claims 2
- 230000004075 alteration Effects 0.000 abstract description 20
- 230000035945 sensitivity Effects 0.000 abstract description 4
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000005331 crown glasses (windows) Substances 0.000 description 5
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 229910052731 fluorine Inorganic materials 0.000 description 4
- 239000011737 fluorine Substances 0.000 description 4
- 230000014509 gene expression Effects 0.000 description 4
- 230000020169 heat generation Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000013473 artificial intelligence Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
Landscapes
- Lenses (AREA)
Abstract
The invention relates to a machine vision lens, comprising: a front lens group, a diaphragm and a rear lens group arranged in order from an object side to an image side along an optical axis; the front lens group consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from the object side to the image side along an optical axis; the rear lens group is composed of a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens which are sequentially arranged from an object side to an image side along an optical axis; the fourth lens and the fifth lens form a cemented lens group; the rear lens group at least comprises two cemented lens groups. The machine vision lens has the characteristics of small chromatic aberration, low distortion, wide field angle, wide working distance range, high focusing efficiency, no heating and low back focus sensitivity.
Description
Technical Field
The present disclosure relates to machine vision lenses, and particularly to a machine vision lens composed of fourteen lenses.
Background
Machine vision is a branch of the rapid development of artificial intelligence, and simply stated, machine vision is to use a machine instead of a human eye to make measurements and decisions. The machine vision system converts the shot target into an image signal through a machine vision product (and an image shooting device, namely CMOS and CCD), and transmits the image signal to a special image processing system to obtain the form information of the shot target, and converts the form information into a digital signal according to the pixel distribution, brightness, color and other information; the image system performs various operations on these signals to extract characteristics of the object, and further controls the operation of the on-site device according to the result of the discrimination.
Currently, machine vision lenses on the market, such as the patent with the patent number of CN203745710U, have a field angle of 33.2 degrees and a narrow focusing field range; the focusing amount is 6.17-8.72mm, and the focusing efficiency is low; for another example, the close-up lens has a patent number of CN101266331, and the close-up lens at least comprises two aspheric surfaces and two focusing structures, which is high in cost. As in the patent of the patent number CN205958826U, the system has no focusing structure and cannot focus on different object distances.
Meanwhile, the existing machine vision lens has the problems of chromatic aberration, poor athermalization effect, narrow working distance range, high back focus sensitivity and the like, and the problems are to be solved.
Disclosure of Invention
An object of the present invention is to provide a machine vision lens having a small chromatic aberration, no heat generation, and low distortion performance.
Another object of the present invention is to provide a machine vision lens with a large angle of view, a wide working distance range, high focusing efficiency, and low back focus sensitivity.
In order to achieve the above object, the present invention provides a machine vision lens comprising: a front lens group, a diaphragm and a rear lens group arranged in order from an object side to an image side along an optical axis;
the front lens group consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from the object side to the image side along an optical axis;
the rear lens group is composed of a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens which are sequentially arranged from an object side to an image side along an optical axis;
the fourth lens and the fifth lens form a cemented lens group;
the rear lens group at least comprises two cemented lens groups.
According to one aspect of the invention, the front lens group is fixedly arranged relative to the imaging surface of the lens, and the diaphragm and the rear lens group can do simultaneous and same-direction linear movement relative to the front lens group.
According to an aspect of the present invention, the first lens and the second lens are both convex-concave lenses along the object-side to image-side direction.
According to one aspect of the invention, the first lens has a focal length f1, the second lens has a focal length f2, and the focal length f1 and the focal length f2 are equal to the focal length f A The following relations are satisfied respectively:
0.4<f1/f A <1.0；
-0.43<f2/f A <-0.15。
according to one aspect of the invention, the front lens group and the rear lens group are both positive power lens groups.
According to one aspect of the present invention, the seventh lens, the ninth lens, the tenth lens, the twelfth lens, and the fourteenth lens are positive power lenses;
the second lens, the third lens, the fourth lens, the eighth lens, and the thirteenth lens are negative power lenses;
the eleventh lens is a positive power lens or a negative power lens.
According to one aspect of the invention, the rear lens group comprises two cemented lens groups;
wherein the eighth lens and the ninth lens form a cemented lens group;
the twelfth lens and the thirteenth lens form a cemented lens group.
According to one aspect of the invention, the rear lens group comprises three cemented lens groups;
wherein the eighth lens and the ninth lens form a cemented lens group;
the tenth lens and the eleventh lens form a cemented lens group;
the twelfth lens and the thirteenth lens form a cemented lens group.
According to one aspect of the invention, the front lens group has a focal length f A The focal length of the rear lens group is f B Focal length f A And focal length f B The relation between them is satisfied: 2.0<f A /f B <4.85。
According to one aspect of the present invention, the fourth lens has a refractive index nd4, an abbe number vd4, and satisfies the following relationship:
1.85<nd4<1.95；
18<vd4<25。
according to one aspect of the present invention, the fifth lens has a refractive index nd5, an abbe number vd5, and satisfies the following relationship:
1.75<nd5<1.90；
20<vd5<25。
according to one aspect of the present invention, the twelfth lens has a refractive index nd12, an abbe number vd12, and satisfies the following relationship:
1.68<nd12<1.80；
48.0<vd12<57.5。
according to one aspect of the present invention, the thirteenth lens has a refractive index nd13, an abbe number vd13, and satisfies the following relation:
1.90<nd13<2.0；
17<vd13<21。
according to one aspect of the invention, at least two lenses of the rear lens group are fluorine crown glass and at least two lenses are heavy flint glass.
According to one aspect of the invention, the seventh lens and the ninth lens are fluorine crown glass, and the eighth lens and the tenth lens are heavy flint glass.
According to one aspect of the present invention, the rear lens group has a moving distance d, which satisfies the relation: 0.45mm < d <0.65mm.
According to one aspect of the invention, the aperture value of the lens is 2.0.
According to the machine vision lens of the present invention, the first lens having positive optical power and the second lens having negative optical power in the front lens group contribute to system distortion correction. The fourth lens and the fifth lens in the front lens group form a cemented lens group, and the rear lens group B at least comprises two cemented lens groups, which is beneficial to correcting chromatic aberration. The diaphragm is arranged between the front lens group and the rear lens group, so that the number of lenses before and after the diaphragm is relatively symmetrical, the front lens group is fixedly arranged relative to an image surface, the diaphragm and the rear lens group can move in the same direction at the same time, the off-axis aberration caused by the change of the object distance can be corrected, the focusing definition can be ensured with a small moving distance in the process of the change of the object distance, and the focusing efficiency is improved. Meanwhile, the structure ensures that the machine vision lens has sufficient back focal length, and clear imaging is ensured under the condition of assembly error allowance.
According to the machine vision lens, the rear lens group adopts the symmetrical structure and comprises five or six positive focal power lenses and three or two negative focal power lenses, wherein the rear lens group at least comprises two glued lenses consisting of the positive focal power lenses and the negative focal power lenses, and can effectively correct spherical aberration, chromatic aberration, distortion and vertical axis aberration. In addition, at least the seventh lens and the ninth lens in the rear lens group are made of fluorite glass, and at least the eighth lens and the tenth lens are made of flint glass. Because of the special refractive index temperature characteristics of the fluorine crown glass and the heavy flint glass, the problem that the imaging surface of the optical system drifts due to temperature is well solved while the chromatic aberration of the optical system is effectively corrected, and athermalization of the optical system is realized.
Drawings
FIG. 1 schematically illustrates a block diagram of a machine vision lens in accordance with one embodiment of the present disclosure;
fig. 2 schematically shows a normal temperature defocus map of the machine vision lens of specific example 1 according to the first embodiment of the present invention;
FIG. 3 schematically illustrates a low temperature-30℃defocus plot of the machine vision lens of example 1 in accordance with the first embodiment of the present invention;
FIG. 4 schematically illustrates a high temperature 70℃defocus plot of a machine vision lens of example 1 in accordance with a first embodiment of the present invention;
fig. 5 schematically shows a distortion diagram of a machine vision lens according to a first embodiment of the present invention, specific example 1;
fig. 6 schematically shows a normal temperature defocus map of the machine vision lens of specific example 2 according to the first embodiment of the present invention;
FIG. 7 schematically illustrates a low temperature-30℃defocus plot of a machine vision lens of example 2 according to a first embodiment of the present invention;
FIG. 8 schematically illustrates a high temperature 70℃defocus plot of a machine vision lens of example 2 according to a first embodiment of the present invention;
fig. 9 schematically shows a distortion diagram of a machine vision lens according to a first embodiment of the present invention, specific example 2;
fig. 10 schematically shows a normal temperature defocus map of the machine vision lens of embodiment 3 according to the first embodiment of the present invention;
FIG. 11 schematically illustrates a low temperature-30℃ defocus plot of the machine vision lens of example 3 in accordance with the first embodiment of the present invention;
FIG. 12 schematically illustrates a high temperature 70℃defocus plot of a machine vision lens of example 3 according to a first embodiment of the present invention;
fig. 13 schematically shows a distortion diagram of a machine vision lens according to a first embodiment of the present invention, embodiment 3;
FIG. 14 schematically illustrates a normal temperature defocus map of a machine vision lens of example 4 according to another embodiment of the present invention;
FIG. 15 schematically illustrates a low temperature-30℃ defocus plot of a machine vision lens of example 4 according to another embodiment of the present invention;
FIG. 16 schematically illustrates a high temperature 70℃ defocus plot of a machine vision lens of example 4 according to another embodiment of the present invention;
FIG. 17 schematically illustrates a distortion map of a machine vision lens of example 4 in accordance with another embodiment of the present invention;
FIG. 18 schematically illustrates a normal temperature defocus map of the machine vision lens of example 5 according to another embodiment of the present invention;
FIG. 19 schematically illustrates a low temperature-30℃ defocus plot of a machine vision lens of example 5 according to another embodiment of the present invention;
FIG. 20 schematically illustrates a high temperature 70℃ defocus plot of a machine vision lens of example 5 according to another embodiment of the present invention;
fig. 21 schematically shows a distortion diagram of a machine vision lens according to another embodiment of the present invention, embodiment 5.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
In describing embodiments of the present invention, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in terms of orientation or positional relationship shown in the drawings for convenience of description and simplicity of description only, and do not denote or imply that the devices or elements in question must have a particular orientation, be constructed and operated in a particular orientation, so that the above terms are not to be construed as limiting the invention.
The present invention will be described in detail below with reference to the drawings and the specific embodiments, which are not described in detail herein, but the embodiments of the present invention are not limited to the following embodiments.
Fig. 1 is a block diagram schematically showing a machine vision lens according to an embodiment of the present invention. As shown in fig. 1, the machine vision lens according to the present invention includes a front lens group a, a stop S, and a rear lens group B arranged in order from an object side to an image side along an optical axis. In the present embodiment, as shown in fig. 1, the front lens group a is composed of a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6, which are arranged in order from the object side to the image side along the optical axis, and the rear lens group B is composed of a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a twelfth lens 12, a thirteenth lens 13, and a fourteenth lens 14, which are arranged in order from the object side to the image side along the optical axis. In the present embodiment, the fourth lens 4 and the fifth lens 5 in the front lens group a constitute a cemented lens group, and the rear lens group B includes at least two cemented lens groups. The machine vision lens provided by the invention has the advantages of small chromatic aberration, better athermalization-free effect and low distortion performance.
In the present embodiment, the front lens group a is fixedly disposed with respect to the imaging surface of the lens, and the stop S and the rear lens group B can be linearly moved simultaneously and in the same direction with respect to the front lens group a. The rear lens group B is movable by a distance d of 0.45mm < d <0.65mm.
According to the machine vision lens of the present invention, the diaphragm S is disposed between the front lens group A and the rear lens group B, the front lens group A includes six lenses in total, the fourth lens 4 and the fifth lens 5 form a cemented lens group, the rear lens group B includes eight lenses in total, and at least two cemented lens groups are included, so that the number of lenses before and after the diaphragm S is relatively symmetrical, which is beneficial to correcting chromatic aberration. The front lens group A is fixedly arranged relative to the image surface, the diaphragm S and the rear lens group B can move in the same direction at the same time, the off-axis aberration caused by the change of the object distance can be corrected, the focusing definition can be ensured by a small moving distance in the process of the change of the object distance, and the focusing efficiency is further improved. Meanwhile, the structure ensures that the machine vision lens has sufficient back focal length, and clear imaging is ensured under the condition of assembly error allowance.
As shown in fig. 1, in the present embodiment, the first lens 1, the fifth lens 5, the sixth lens 6, the seventh lens 7, the ninth lens 9, the tenth lens 10, the twelfth lens 12, and the fourteenth lens 14 are positive power lenses. The second lens 2, the third lens 3, the fourth lens 4, the eighth lens 8 and the thirteenth lens 13 are negativeAn optical power lens. The eleventh lens 11 may be a positive power lens or a negative power lens. The front lens group A and the rear lens group B are lens groups with positive focal power, wherein the focal length of the front lens group A is f A The focal length of the rear lens group B is f B Focal length f A And focal length f B The following are satisfied: 2.0<f A /f B <4.85. This arrangement is advantageous for correcting distortion of the machine vision lens.
As shown in fig. 1, according to the machine vision lens of the present invention, the first lens 1 and the second lens 2 in the front lens group a are both convex-concave lenses along the direction from the object side to the image side of the optical axis. Wherein the focal length of the first lens 1 is f1, the focal length of the second lens 2 is f2, and the focal length f1 and the focal length f2 are equal to the focal length f of the front lens group A A Respectively satisfy the relation 0.4<f1/f A <1.0 and-0.43<f2/f A <-0.15. According to the arrangement of the first lens 1 and the second lens 2, a large field angle of the machine vision lens can be realized, and the wide-angle image capturing and shooting is facilitated.
As shown in fig. 1, in the present embodiment, according to the machine vision lens of the present invention, the fourth lens 4 and the fifth lens 5 in the front lens group a constitute a cemented lens group. The fourth lens 4 has a refractive index nd4, an abbe number vd4, and satisfies the relations 1.85< nd4<1.95 and 18< vd4<25. The refractive index of the fifth lens 5 is nd5, the abbe number is vd5, and the following relational expressions 1.75< nd5<1.9 and 20< vd5<25 are satisfied. In the present embodiment, the eighth lens 8 and the ninth lens 9 in the rear lens group B constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group. The twelfth lens 12 has a refractive index nd12, an abbe number vd12, and satisfies the relations 1.68< nd12<1.80 and 48.0< vd12<57.5. The thirteenth lens 13 has a refractive index nd13, an abbe number vd13, and satisfies the relations 1.90< nd13<2.0 and 17< vd13<21.
According to another embodiment of the present invention, the rear lens group B includes 3 cemented lens groups, wherein the eighth lens 8 and the ninth lens 9 form a cemented lens group, the tenth lens 10 and the eleventh lens 11 form a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 form a cemented lens group. Wherein the twelfth lens 12 has a refractive index nd12, an abbe number vd12, and the following relational expressions 1.68< nd12<1.80 and 48.0< vd12<57.5 are satisfied. The thirteenth lens 13 has a refractive index nd13, an abbe number vd13, and satisfies the following relational expressions 1.90< nd13<2.0 and 17< vd13<21.
According to the machine vision lens of the present invention, the rear lens group B includes five or six positive power lenses and three or two negative power lenses, i.e., the power of the eleventh lens may be changed, either positive or negative, wherein the eighth lens 8 and the ninth lens 9 constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group, so that the rear lens group B has a symmetrical structure as a whole, which is based on the structure of both ends of the center of the rear lens group being substantially the same, and such a structure can effectively correct spherical aberration, distortion, and vertical aberration. In the rear lens group B, at least the seventh lens 7 and the ninth lens 9 are made of fluoric crown glass, and at least the eighth lens 8 and the tenth lens 10 are made of flint glass. Because of the special refractive index temperature characteristics of the fluorine crown glass and the heavy flint glass, the problem that the imaging surface of the optical system drifts due to temperature is well solved while the chromatic aberration of the optical system is effectively corrected, and athermalization of the optical system is realized.
The following are three sets of examples given to illustrate the machine vision lens according to the present invention in detail, with respect to the variation of the material of each lens and the variation of each relevant parameter according to the first embodiment of the present invention. According to the first embodiment of the present invention, the fourth lens and the fifth lens in the front lens group a constitute a cemented lens group, and the rear lens group B includes two cemented lens groups therein, wherein the eighth lens 8 and the ninth lens 9 constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group. So fourteen lenses have 26 faces in total. The 26 faces are arranged in order according to the structural order of the present invention, and for convenience of description, the 26 faces are numbered S1 to S26.
The data in the three sets of examples are as in table 1 below:
TABLE 1
According to embodiment 1 of the present invention, as can be seen from Table 1, the focal length f of the front group lens A A Focal length f with rear group lens B B Satisfy f between A /f B =2.01. Focal length f1 of the first lens 1 and focal length f of the front group lens A A Satisfy f1/f A =0.93. Focal length f2 of the second lens 2 and focal length f of the front group lens A A Satisfies f2/f A ＝-0.43。
Table 2 below lists the distance of the stop S from the front lens group a at different object distances:
| object distance (mm) | Infinity distance | 1000 | 400 | 100 |
| dst | 10.62 | 10.55 | 10.45 | 10 |
TABLE 2
In this embodiment, the focal length of each lens in the machine vision lens is f1=30.31 mm, f2= -13.98mm, f3= -11.95mm, f4= -7.50mm, f5=8.83 mm, f6=17.44 mm, f7=28.49 mm, f8= -6.53mm, f9=15.40 mm, f10=11.09 mm, f11= -140.36mm, f12=12.92 mm, f13= -6.50mm, and f14=12.32 mm. The parameters of each optical system of the machine vision lens are as follows, the object distance is 0.4m, the total length in the optical system is 59mm, the focal length of the system is 8.2mm, the aperture value is 2.0, the angle of view in the diagonal direction is 70 degrees, and the photosensitive chip is a 2/3' photosensitive chip. As can be seen from table 2, in the present embodiment, the distance between the stop S and the front lens group a is 10.45mm.
Table 3 below lists relevant parameters for each lens, including surface type, radius of curvature, thickness, refractive index of the material, and abbe number:
TABLE 3 Table 3
In the present embodiment, referring to fig. 1, the fourth lens 4 and the fifth lens 5 in the front lens group a constitute a cemented lens group, the eighth lens 8 and the ninth lens 9 in the rear lens group B constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group. As can be seen from table 3, in the present embodiment, the object side surfaces and the image side surfaces of all lenses of the machine vision lens are spherical surfaces.
As can be seen from table 3, the refractive indexes and abbe numbers of the fourth lens 4, the fifth lens 5, the twelfth lens 12 and the thirteenth lens 13 in the cemented lens group all meet the requirements of the machine vision lens according to the present invention.
Fig. 2 to 5 are diagrams schematically showing defocus curves and distortion charts of the machine vision lens of example 1 according to the present invention at normal temperature, low temperature-30 ℃ and high temperature 70 ℃. As can be seen from the figure, when the aperture value of the machine vision lens is 2.0 and the working object distance is 400mm, the defocus (i.e. the focal depth range of the lens) of the lens is controlled within the range of-0.006 mm to 0.006mm at normal temperature, low temperature of-30 ℃ and high temperature of 70 ℃, and the distortion rate of the lens is controlled within the range of-4%. Therefore, according to the machine vision lens of the embodiment 1 of the present invention, under the conditions of realizing a large field angle, a wide working range and high focusing efficiency, a high resolution can still be ensured at extremely low and extremely high temperatures, and athermalization of the machine vision lens is realized. Meanwhile, the aberration rate of the lens is low, and the definition of an image plane and no distortion are ensured.
According to embodiment 2 of the present invention, as can be seen from Table 1, the focal length f of the front group lens A A Focal length f with rear group lens B B Satisfy f between A /f B =2.2. Focal length f1 of the first lens 1 and focal length f of the front group lens A A Satisfy f1/f A =0.97. Focal length f2 of the second lens 2 and focal length f of the front group lens A A Satisfies f2/f A ＝-0.41。
Table 4 below lists the distance of the stop S from the front lens group A at different object distances:
| object distance (mm) | Infinity distance | 1000 | 400 | 100 |
| dst(mm) | 10.90 | 10.83 | 10.72 | 10.26 |
TABLE 4 Table 4
In this embodiment, the focal length of each lens in the machine vision lens is f1=33.88 mm, f2= -14.43mm, f3= -13.04mm, f4= -9.27mm, f5=10.84 mm, f6=18.75 mm, f7=21.15 mm, f8= -5.99mm, f9=15.31 mm, f10=12.88 mm, f11=66.22 mm, f12=26.68 mm, f13= -9.29mm, and f14=13.67 mm. The parameters of each optical system of the machine vision lens are as follows, the object distance is 0.4m, the total length in the optical system is 59mm, the focal length of the system is 8.3mm, the aperture value is 2.3, the angle of view in the diagonal direction is 70 degrees, and the photosensitive chip is a 2/3' photosensitive chip. As can be seen from table 4, in the present embodiment, the distance between the stop S and the front lens group a is 10.72mm.
Table 5 below lists relevant parameters for each lens, including surface type, radius of curvature, thickness, refractive index of the material, and abbe number:
TABLE 5
In the present embodiment, referring to fig. 1, the fourth lens 4 and the fifth lens 5 in the front lens group a constitute a cemented lens group, the eighth lens 8 and the ninth lens 9 in the rear lens group B constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group. As can be seen from table 5, in the present embodiment, the object side surfaces and the image side surfaces of all lenses of the machine vision lens are spherical surfaces.
As can be seen from table 5, the refractive indexes and abbe numbers of the fourth lens 4, the fifth lens 5, the twelfth lens 12 and the thirteenth lens 13 in the cemented lens group all meet the requirements of the machine vision lens according to the present invention.
Fig. 6 to 9 are a graph schematically showing defocus curves and distortion charts of a machine vision lens according to embodiment 2 of the present invention at normal temperature, low temperature-30 ℃ and high temperature 70 ℃. As can be seen from the figure, when the aperture value of the machine vision lens is 2.3 and the working object distance is 400mm, the defocus (i.e. the focal depth range of the lens) of the lens is controlled within the range of-0.006 mm to 0.006mm at normal temperature, low temperature of-30 ℃ and high temperature of 70 ℃, and the distortion rate of the lens is controlled within the range of-2%. Therefore, according to the machine vision lens of embodiment 2 of the present invention, under the conditions of realizing a large angle of view, a wide working range and high focusing efficiency, high resolution can still be ensured at extremely low and extremely high temperatures, and athermalization of the machine vision lens is realized. Meanwhile, the aberration rate of the lens is low, and the definition of an image plane and no distortion are ensured.
According to embodiment 3 of the present invention, as can be seen from Table 1, the focal length f of the front group lens A A Focal length f with rear group lens B B Satisfy f between A /f B =4.45. Focal length f1 of the first lens 1 and focal length f of the front group lens A A Satisfy f1/f A =0.55. Focal length f2 of the second lens 2 and focal length f of the front group lens A A Satisfies f2/f A ＝-0.19。
Table 6 below lists the distance of the stop S from the front lens group a at different object distances:
| object distance (mm) | Infinity distance | 1000 | 400 | 100 |
| dst(mm) | 9.723 | 9.662 | 9.574 | 9.185 |
TABLE 6
In this embodiment, the focal length of each lens in the machine vision lens is f1=36.79 mm, f2= -12.97mm, f3= -16.03mm, f4= -8.27mm, f5=10.54 mm, f6=19.04 mm, f7=32.17 mm, f8= -5.84mm, f9=12.05 mm, f10=9.94 mm, f11= -72.07mm, f12=10.44 mm, f13= -5.84mm, and f14=12.13 mm. The parameters of each optical system of the machine vision lens are as follows, the object distance is 0.4m, the total length in the optical system is 59mm, the focal length of the system is 8.0mm, the aperture value is 2.4, the angle of view in the diagonal direction is 78 degrees, and the photosensitive chip is a 2/3' photosensitive chip. As can be seen from table 6, in the present embodiment, the distance between the stop S and the front lens group a is 9.574mm.
Table 7 below lists relevant parameters for each lens, including surface type, radius of curvature, thickness, refractive index of the material, and abbe number:
TABLE 7
In the present embodiment, referring to fig. 1, the fourth lens 4 and the fifth lens 5 in the front lens group a constitute a cemented lens group, the eighth lens 8 and the ninth lens 9 in the rear lens group B constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group. As can be seen from table 7, in the present embodiment, the object side surfaces and the image side surfaces of all lenses of the machine vision lens are spherical surfaces.
As can be seen from table 7, the refractive indexes and abbe numbers of the fourth lens 4, the fifth lens 5, the twelfth lens 12 and the thirteenth lens 13 in the cemented lens group all meet the requirements of the machine vision lens according to the present invention.
Fig. 10 to 13 are a graph schematically showing defocus curves and distortion charts of a machine vision lens of example 3 according to the present invention at normal temperature, low temperature-30 c, and high temperature 70 c. As can be seen from the figure, when the aperture value of the machine vision lens is 2.4 and the working object distance is 400mm, the defocus (i.e. the focal depth range of the lens) of the lens is controlled within the range of-0.006 mm to 0.006mm at normal temperature, low temperature of-30 ℃ and high temperature of 70 ℃, and the distortion rate of the lens is controlled within the range of-4%. It can be seen that the machine vision lens according to the fifth embodiment of the present invention also has the advantages of small chromatic aberration, no heat generation, low distortion rate, wider angle of view, and wider working distance range.
The following are two sets of examples given to illustrate the machine vision lens according to the present invention in detail, with respect to the variation of the materials of the individual lenses and the differences in the respective relevant parameters according to another embodiment of the present invention. According to another embodiment of the present invention, the fourth lens and the fifth lens in the front lens group a constitute a cemented lens group, and the rear lens group B includes three cemented lens groups therein, wherein the eighth lens 8 and the ninth lens 9 constitute a cemented lens group, the tenth lens 10 and the eleventh lens 11 constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group. So fourteen lenses have 25 faces in total. The 25 faces are arranged in order according to the structural order of the present invention, and for convenience of description, the 25 faces are numbered S1 to S25.
The data for both sets of examples are as shown in table 8 below:
| conditional expression | Example 4 | Example 5 |
| f A /f B | 4.47 | 4.82 |
| f1/f A | 0.42 | 0.49 |
| f2/f A | -0.19 | -0.21 |
| nd4 | 1.92 | 1.92 |
| vd4 | 18.90 | 18.90 |
| nd5 | 1.85 | 1.85 |
| vd5 | 24.80 | 24.80 |
| nd12 | 1.70 | 1.73 |
| vd12 | 55.53 | 54.67 |
| nd13 | 1.92 | 1.95 |
| vd13 | 20.88 | 17.94 |
| D | 0.593 | 0.458 |
TABLE 8
According to embodiment 4 of the present invention, as can be seen from Table 8, the focal length f of the front group lens A A Focal length f with rear group lens B B Satisfy f between A /f B =4.47. Focal length f1 of the first lens 1 and focal length f of the front group lens A A Satisfy f1/f A =0.42. Focal length f2 of the second lens 2 and focal length f of the front group lens A A Satisfies f2/f A ＝-0.19。
Table 9 below lists the distance of the stop S from the front lens group a at different object distances:
| object distance (mm) | Infinity distance | 1000 | 400 | 100 |
| dst(mm) | 13.083 | 13.023 | 12.923 | 12.49 |
TABLE 9
In this embodiment, the focal length of each lens in the machine vision lens is f1=29.48 mm, f2= -13.41mm, f3= -13.42mm, f4= -11.46mm, f5=13.23 mm, f6=21.26 mm, f7=16.26 mm, f8= -6.68mm, f9=14.55 mm, f10=8.96 mm, f11= -33.95mm, f12=20.91 mm, f13= -7.99mm, and f14=17.11 mm. The parameters of each optical system of the machine vision lens are as follows, the object distance is 0.4m, the total length in the optical system is 59mm, the focal length of the system is 8.3mm, the aperture value is 2.3, the angle of view in the diagonal direction is 70 degrees, and the photosensitive chip is a 2/3' photosensitive chip. As can be seen from table 9, in the present embodiment, the distance between the stop S and the front lens group a is 12.923mm.
Table 10 below lists relevant parameters for each lens, including surface type, radius of curvature, thickness, refractive index of the material, and abbe number:
table 10
In the present embodiment, the fourth lens 4 and the fifth lens 5 in the front lens group a constitute a cemented lens group, and the rear lens group B includes three cemented lens groups, of which the eighth lens 8 and the ninth lens 9 constitute a cemented lens group, the tenth lens 10 and the eleventh lens 11 constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group. As can be seen from table 10, in the present embodiment, the object side surfaces and the image side surfaces of all the lenses of the machine vision lens are spherical surfaces.
As can be seen from table 10, the refractive indices and abbe numbers of the fourth lens 4, the fifth lens 5, the twelfth lens 12 and the thirteenth lens 13 in the cemented lens group all meet the requirements of the machine vision lens according to the present invention.
Fig. 14 to 17 are a graph schematically showing defocus curves and distortion charts of a machine vision lens according to embodiment 4 of the present invention at normal temperature, low temperature-30 ℃ and high temperature 70 ℃. As can be seen from the figure, when the aperture value of the machine vision lens is 2.3 and the working object distance is 400mm, the defocus (i.e. the focal depth range of the lens) of the lens is controlled within the range of-0.006 mm to 0.006mm at normal temperature, low temperature of-30 ℃ and high temperature of 70 ℃, and the distortion rate of the lens is controlled within the range of-5%. It can be seen that the machine vision lens according to embodiment 4 of the present invention also has the characteristics of small chromatic aberration, no heating, low distortion, wide angle of view, wide working distance range, high focusing efficiency, and low back focus sensitivity.
According to embodiment 5 of the present invention, as can be seen from Table 8, the focal length f of the front group lens A A Focal length f with rear group lens B B Satisfy f between A /f B =4.82. Focal length f1 of the first lens 1 and focal length f of the front group lens A A Satisfy f1/f A =0.49. Focal length f2 of the second lens 2 and focal length f of the front group lens A A Satisfies f2/f A ＝-0.21。
Table 11 below lists the distance of the stop S from the front lens group A at different object distances:
| object distance (mm) | Infinity distance | 1000 | 400 | 100 |
| dst(mm) | 11.433 | 11.385 | 11.309 | 10.975 |
TABLE 11
In this embodiment, the focal length of each lens in the machine vision lens is f1=32.15 mm, f2= -13.92mm, f3= -12.82mm, f4= -8.87mm, f5=10.94 mm, f6=19.35 mm, f7=31.21 mm, f8= -7.07mm, f9=14.25 mm, f10=7.7 mm, f11= -23.71mm, f12=10.44 mm, f13= -5.57mm, and f14=13.09 mm. The parameters of each optical system of the machine vision lens are as follows, the object distance is 0.4m, the total length in the optical system is 59mm, the focal length of the system is 7.3mm, the aperture value is 2.3, the angle of view in the diagonal direction is 80 degrees, and the photosensitive chip is a 2/3' photosensitive chip. As can be seen from table 11, in the present embodiment, the distance between the stop S and the front lens group a is 11.309mm.
Table 12 below lists relevant parameters for each lens, including surface type, radius of curvature, thickness, refractive index of the material, and abbe number:
table 12
In the present embodiment, the fourth lens 4 and the fifth lens 5 in the front lens group a constitute a cemented lens group, and the rear lens group B includes three cemented lens groups, of which the eighth lens 8 and the ninth lens 9 constitute a cemented lens group, the tenth lens 10 and the eleventh lens 11 constitute a cemented lens group, and the twelfth lens 12 and the thirteenth lens 13 constitute a cemented lens group. As can be seen from table 12, in the present embodiment, the object side surfaces and the image side surfaces of all lenses of the machine vision lens are spherical surfaces.
As can be seen from table 12, the refractive indexes and abbe numbers of the fourth lens 4, the fifth lens 5, the twelfth lens 12 and the thirteenth lens 13 in the cemented lens group all meet the requirements of the machine vision lens according to the present invention.
Fig. 18 to 21 are a graph schematically showing defocus curves and distortion curves of the machine vision lens of example 5 according to the present invention at normal temperature, low temperature-30 c, and high temperature 70 c. As can be seen from the figure, when the aperture value of the machine vision lens is 2.3 and the working object distance is 400mm, the defocusing (namely the depth of field range of the lens) of the lens is controlled within the range of-0.006 mm to 0.006mm at normal temperature, low temperature of-30 ℃ and high temperature of 70 ℃, and the distortion rate of the lens is controlled within the range of-2%. It can be seen that the machine vision lens according to the fourth embodiment of the present invention also has the advantages of small chromatic aberration, no heat generation, low distortion rate, wider angle of view, and wider working distance range.
The foregoing is merely exemplary of embodiments of the invention and, as regards devices and arrangements not explicitly described in this disclosure, it should be understood that this can be done by general purpose devices and methods known in the art.
The above description is only one embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (16)
1. A machine vision lens, comprising: a front lens group (A), a diaphragm (S) and a rear lens group (B) which are arranged in order from an object side to an image side along an optical axis;
the front lens group (A) is composed of a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5) and a sixth lens (6) which are sequentially arranged from an object side to an image side along an optical axis;
the rear lens group (B) is composed of a seventh lens (7), an eighth lens (8), a ninth lens (9), a tenth lens (10), an eleventh lens (11), a twelfth lens (12), a thirteenth lens (13) and a fourteenth lens (14) which are arranged in order from the object side to the image side along the optical axis;
the fourth lens (4) and the fifth lens (5) form a cemented lens group;
the rear lens group (B) comprises at least two glued lens groups;
the first lens (1), the fifth lens (5), the sixth lens (6), the seventh lens (7), the ninth lens (9), the tenth lens (10), the twelfth lens (12) and the fourteenth lens (14) are positive power lenses;
the second lens (2), the third lens (3), the fourth lens (4), the eighth lens (8) and the thirteenth lens (13) are negative power lenses;
the eleventh lens (11) is a positive power lens or a negative power lens.
2. Machine vision lens according to claim 1, characterized in that the front lens group (a) is fixedly arranged with respect to the imaging plane of the lens, the diaphragm (S) and the rear lens group (B) being simultaneously linearly movable in the same direction with respect to the front lens group (a).
3. Machine vision lens according to claim 2, characterized in that the first lens (1) and the second lens (2) are both convex-concave lenses along the object-side to image-side direction.
4. A machine vision lens according to claim 3, characterized in that the first lens (1) has a focal length f1, the second lens (2) has a focal length f2, the focal length f1 and the focal length f2 and the focal length f A The following relations are satisfied respectively:
0.4<f1/f A <1.0；
-0.43<f2/f A <-0.15。
5. machine vision lens according to claim 4, characterized in that the front lens group (a) and the rear lens group (B) are both positive power lens groups.
6. The machine vision lens of claim 5, wherein the rear lens group (B) comprises two glue lens groups;
wherein the eighth lens (8) and the ninth lens (9) constitute a cemented lens group;
the twelfth lens (12) and the thirteenth lens (13) constitute a cemented lens group.
7. The machine vision lens of claim 5, wherein the rear lens group (B) comprises three glue lens groups;
wherein the eighth lens (8) and the ninth lens (9) constitute a cemented lens group;
-said tenth lens (10) and said eleventh lens (11) constitute a cemented lens group;
the twelfth lens (12) and the thirteenth lens (13) constitute a cemented lens group.
8. Machine vision lens according to one of claims 1 to 7, characterized in that the front lens group (a) has a focal length f A The focal length of the rear lens group (B) is f B Focal length f A And focal length f B The relation between them is satisfied: 2.0<f A /f B <4.85。
9. Machine vision lens according to one of claims 1 to 7, characterized in that the fourth lens (4) has a refractive index nd4, an abbe number vd4, and the following relation is satisfied:
1.85<nd4<1.95；
18<vd4<25。
10. the machine vision lens according to claim 9, characterized in that the refractive index of the fifth lens (5) is nd5, the abbe number is vd5, and the following relation is satisfied:
1.75<nd5<1.90；
20<vd5<25。
11. machine vision lens according to one of claims 1 to 7, characterized in that the twelfth lens (12) has a refractive index nd12, an abbe number vd12 and satisfies the following relation:
1.68<nd12<1.80；
48.0<vd12<57.5。
12. the machine vision lens according to claim 11, characterized in that the thirteenth lens (13) has a refractive index nd13, an abbe number vd13, and the following relation is satisfied:
1.90<nd13<2.0；
17<vd13<21。
13. the machine vision lens of claim 12, wherein at least two of the lenses in the rear lens group (B) are fluorite glass and at least two of the lenses are heavy flint glass.
14. The machine vision lens according to claim 13, characterized in that the seventh lens (7) and the ninth lens (9) are a fluorite glass, and the eighth lens (8) and the tenth lens (10) are a heavy flint glass.
15. The machine vision lens according to claim 14, characterized in that the rear lens group (B) has a moving distance d, which satisfies the relation: 0.45mm < d <0.65mm.
16. The machine vision lens of claim 15, wherein the lens has an aperture value of 2.0.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710846357.5A CN107608051B (en) | 2017-09-19 | 2017-09-19 | Machine vision lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710846357.5A CN107608051B (en) | 2017-09-19 | 2017-09-19 | Machine vision lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107608051A CN107608051A (en) | 2018-01-19 |
| CN107608051B true CN107608051B (en) | 2024-02-23 |
Family
ID=61060977
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710846357.5A Active CN107608051B (en) | 2017-09-19 | 2017-09-19 | Machine vision lens |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107608051B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109212718B (en) * | 2018-08-31 | 2024-07-12 | 舜宇光学(中山)有限公司 | Imaging system |
| CN109116521B (en) * | 2018-10-22 | 2024-07-16 | 舜宇光学(中山)有限公司 | Imaging system |
| CN109633874B (en) * | 2019-01-23 | 2024-02-02 | 广东奥普特科技股份有限公司 | Telecentric lens |
| CN109739005A (en) * | 2019-01-29 | 2019-05-10 | 上海鼎州光电科技有限公司 | A kind of nearly eye detector lens |
| CN109709665B (en) * | 2019-02-27 | 2024-03-05 | 光虎光电科技(天津)有限公司 | Double telecentric lens and optical system |
| CN115185072B (en) * | 2022-06-01 | 2024-03-12 | 广东北创光电科技股份有限公司 | Aspheric wide-angle long flange video lens |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4883345A (en) * | 1983-12-02 | 1989-11-28 | Nikon Corporation | Projection optical apparatus |
| US5999310A (en) * | 1996-07-22 | 1999-12-07 | Shafer; David Ross | Ultra-broadband UV microscope imaging system with wide range zoom capability |
| CN101907765A (en) * | 2009-06-04 | 2010-12-08 | 鸿富锦精密工业（深圳）有限公司 | Optical zoom lens and imaging module |
| CN102033297A (en) * | 2009-10-05 | 2011-04-27 | 佳能株式会社 | Optical system and optical device including the same |
| CN104570301A (en) * | 2015-01-05 | 2015-04-29 | 舜宇光学(中山)有限公司 | Constant-aperture wide-angle varifocus objective |
| CN207216112U (en) * | 2017-09-19 | 2018-04-10 | 舜宇光学(中山)有限公司 | Machine visual lens |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6452285B2 (en) * | 2013-11-22 | 2019-01-16 | キヤノン株式会社 | Zoom lens and imaging apparatus having the same |
-
2017
- 2017-09-19 CN CN201710846357.5A patent/CN107608051B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4883345A (en) * | 1983-12-02 | 1989-11-28 | Nikon Corporation | Projection optical apparatus |
| US5999310A (en) * | 1996-07-22 | 1999-12-07 | Shafer; David Ross | Ultra-broadband UV microscope imaging system with wide range zoom capability |
| CN101907765A (en) * | 2009-06-04 | 2010-12-08 | 鸿富锦精密工业（深圳）有限公司 | Optical zoom lens and imaging module |
| CN102033297A (en) * | 2009-10-05 | 2011-04-27 | 佳能株式会社 | Optical system and optical device including the same |
| CN104570301A (en) * | 2015-01-05 | 2015-04-29 | 舜宇光学(中山)有限公司 | Constant-aperture wide-angle varifocus objective |
| CN207216112U (en) * | 2017-09-19 | 2018-04-10 | 舜宇光学(中山)有限公司 | Machine visual lens |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107608051A (en) | 2018-01-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107608051B (en) | Machine vision lens | |
| CN106199921B (en) | Wide-angle lens | |
| CN106483632B (en) | Optical imaging system | |
| CN105572842B (en) | Optical imaging system | |
| CN105319688B (en) | Optical imaging system | |
| CN106154498B (en) | Optical imaging system | |
| CN107272144A (en) | Optical imaging system | |
| KR101431548B1 (en) | Lens optical system | |
| CN106483631A (en) | Optical imaging system | |
| CN105629443A (en) | Lens system and camera lens | |
| CN106468821A (en) | Optical imaging system | |
| CN108139569A (en) | Wide-angle lens | |
| CN105334598B (en) | A kind of optical lens | |
| CN105308491A (en) | Fixed-focal-length lens system | |
| US11635599B2 (en) | Three-piece infrared single wavelength projection lens system | |
| CN107966798B (en) | Short focus projection objective | |
| CN205067847U (en) | Optical lens | |
| CN100476493C (en) | Image pickup optical system | |
| CN109085694A (en) | Five chip broad angle lens groups | |
| CN106772947A (en) | Big motion DV camera lenses of practising physiognomy | |
| CN207216112U (en) | Machine visual lens | |
| CN104345429A (en) | Optical system of camera adapter for endoscope | |
| CN101833160B (en) | Image taking optical lens system | |
| CN108983402A (en) | Large aperture camera lens | |
| CN100547452C (en) | Zoom lens |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |