CN219657942U - Light-weight wide-angle lens with large flying load and large athermal aberration - Google Patents
Light-weight wide-angle lens with large flying load and large athermal aberration Download PDFInfo
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- CN219657942U CN219657942U CN202320673889.4U CN202320673889U CN219657942U CN 219657942 U CN219657942 U CN 219657942U CN 202320673889 U CN202320673889 U CN 202320673889U CN 219657942 U CN219657942 U CN 219657942U
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- 230000003287 optical effect Effects 0.000 claims abstract description 31
- 230000008859 change Effects 0.000 claims abstract description 11
- 239000005387 chalcogenide glass Substances 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 229910052732 germanium Inorganic materials 0.000 claims description 6
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 6
- 238000003384 imaging method Methods 0.000 abstract description 12
- 238000005516 engineering process Methods 0.000 abstract description 6
- 230000008030 elimination Effects 0.000 abstract description 3
- 238000003379 elimination reaction Methods 0.000 abstract description 3
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- 238000012544 monitoring process Methods 0.000 description 11
- 230000009286 beneficial effect Effects 0.000 description 4
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- 238000004458 analytical method Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000007723 die pressing method Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- PFNQVRZLDWYSCW-UHFFFAOYSA-N (fluoren-9-ylideneamino) n-naphthalen-1-ylcarbamate Chemical compound C12=CC=CC=C2C2=CC=CC=C2C1=NOC(=O)NC1=CC=CC2=CC=CC=C12 PFNQVRZLDWYSCW-UHFFFAOYSA-N 0.000 description 1
- 241000251468 Actinopterygii Species 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
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- 239000011593 sulfur Substances 0.000 description 1
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Abstract
The utility model discloses a light-weight flight load large-breadth athermal wide-angle lens, which comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from an object side to a target surface; the first lens is a negative focal power lens with a convex surface facing the object side; the second lens is a positive focal power lens with a convex surface facing the object side; the third lens is a positive focal power lens with a concave surface facing the object side; the fourth lens is a positive focal power lens with a concave surface facing the object side. The utility model adopts the technology of optical passive heat difference elimination, the horizontal angle of view reaches 140 degrees, the diagonal angle of view can reach 168.9 degrees, the temperature change range is-40 degrees to +80 degrees, and the application range is wide; the imaging breadth is large, the imaging system can be used for 640 cores, the image surface can reach 17um, and the light quantity of the optical system is large; the F number of the system is 1.2, the caliber of the whole optical lens is small, and the cost can be saved to the greatest extent; the device has the characteristics of light weight, wide working wave band, compact structure, good fitting property, good imaging quality, transfer function reaching or approaching the diffraction limit and the like.
Description
Technical Field
The utility model relates to a light-weight wide-angle lens with large flying load and large athermal aberration, and belongs to the technical field of wide-angle lenses.
Background
At present, the infrared lens has great demands in the aspects of business and civil use, and the infrared imaging technology is widely applied to the fields of national defense, industry, medical treatment, electric power detection, intelligent home and the like, and has great application prospect and market value. The long-wave infrared wide-angle fisheye lens is a special lens with the angle of view reaching or approaching 180 degrees. The front lens of the lens is generally of negative focal power, plays an important role in forest fire prevention monitoring, sky monitoring, ground patrol, intelligent home, airport monitoring, transformer substation monitoring and the like, has a large temperature change range in special occasions, leads to the reduction of the image quality of an optical system target surface along with temperature deviation, and needs to adopt athermalization design for the optical system; but commercial fish-eye lenses typically have 100% distortion in the diagonal field of view, in which case the edges will be much lower energy than the center due to uniformity effects, unless very high energy objects are detected, some images will be available.
CN 106547074A discloses a five-piece type infrared fisheye lens, but no technology of optical passive athermalization is involved; the fish eye disclosed in CN 208110150U is very long, is unfavorable for light object load, and the aspheric surface is too much to use simultaneously, and the aspheric surface degree of curvature is big, is unfavorable for processing, and the equipment yield is poor. The fish-eye lens disclosed in CN 115128774A is designed in a 5-piece type, has a relatively heavy weight and a long length, and the head piece is made of a sulfur material, so that the fish-eye lens is not beneficial to use in an outdoor environment, and is not beneficial to civil development due to the fact that a relatively expensive zinc selenide material is used.
Disclosure of Invention
Aiming at the defects of the technology, the utility model discloses a large-breadth long-wave infrared optical passive athermalization fisheye lens suitable for a 640x512 infrared machine core, provides a large-target-surface long-wave infrared fisheye lens optical passive athermalization solution, and is suitable for forest fire prevention monitoring, sky monitoring, ground patrol, intelligent home, airport, transformer substation monitoring and other aspects.
In order to solve the technical problems, the technical scheme adopted by the utility model is as follows:
a light-weight flight load large-breadth athermalized wide-angle lens comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from an object side to a target surface; the first lens is a negative focal power lens with a convex surface facing the object side; the second lens is a positive focal power lens with a convex surface facing the object side; the third lens is a positive focal power lens with a concave surface facing the object side; the fourth lens is a positive focal power lens with a concave surface facing the object side.
In order to ensure the rear working distance BFL, the utility model adopts a reverse shooting remote structure, and satisfies the following relation:
BFL/f’>2.45；-3<f1’/f’<0；2<f5’/f’<4；-10<f1’<-5；15<f2’<20；70<f3’<75；10<f4’<15；
wherein BFL is the back focal length, and f1' is the focal length of the first lens; f2' is the focal length of the second lens; f3' is the focal length of the third lens; f4' is the focal length of the fourth lens; f5' is the combined focal length of the second lens, the third lens and the fourth lens; f' is the lens combined focal length.
In order to correct aberration and eliminate the influence of temperature change, germanium is matched with chalcogenide glass material, and the first lens adopts high-refractive-index germanium, so that the aberration correction is facilitated, and meanwhile, a hard carbon film is conveniently plated on the front surface; the other three sheets adopt chalcogenide glass with lower refractive index temperature change coefficient dn/dT for eliminating adverse effect of temperature change on image quality.
The lens is suitable for 640x512-17um infrared cores, and is a wide-angle fisheye lens for light-weight unmanned aerial vehicle large-format long-wave infrared optics passive athermalization.
The lens is suitable for occasions with large temperature change range such as forest fire prevention monitoring, public security and side protection warning, and is especially suitable for unmanned aerial vehicle observation in high-altitude operation with light weight.
In order to achieve both miniaturization and imaging quality, the center thickness of the first lens is 2+/-0.002 mm; the center thickness of the second lens is 2+/-0.002 mm; the center thickness of the third lens is 2.5+/-0.002 mm; the center thickness of the fourth lens is 3.7.+ -. 0.002mm. The center interval between the first lens and the second lens is 13.533 plus or minus 0.002mm; the center spacing between the second lens and the third lens is 0.469 + -0.002 mm; the center spacing between the third lens and the fourth lens is 5±0.002mm.
In order to improve imaging quality, the object side surface of the first lens is a spherical surface, and the image side surface of the first lens is a spherical surface; the object side surface of the second lens is an aspheric surface, and the image side surface of the second lens is a spherical surface; the object side surface of the third lens is an aspheric surface, and the image side surface of the third lens is a diffraction surface; the fourth lens element has an aspheric object-side surface and an image-side surface.
In order to further improve imaging quality, the curvature radius of the object side surface of the first lens is-1.39+/-0.002 mm, and the curvature radius of the image side surface of the first lens is-0.84+/-0.002 mm; the curvature radius of the object side surface of the second lens is 1.28 plus or minus 0.002mm, and the curvature radius of the image side surface of the second lens is 4.23 plus or minus 0.002mm; the curvature radius of the object side surface of the third lens is-0.26+/-0.002 mm, and the curvature radius of the image side surface of the third lens is-0.26+/-0.002 mm; the radius of curvature of the object side of the fourth lens is-3.17+/-0.002 mm, and the radius of curvature of the image side of the fourth lens is 1.24+/-0.002 mm.
The applicable wave band of the lens is 8-14um, the F number of the optical system is equal to 1.2, the horizontal view angle is 140 degrees, the diagonal view angle is 168.9 degrees, and the temperature change range is-40 degrees to +80 degrees.
The technology not mentioned in the present utility model refers to the prior art.
The light-weight flight load large-breadth athermalized wide-angle lens has the following beneficial effects:
1) The technology of optical passive athermal is adopted, the horizontal view angle reaches 140 degrees, the diagonal view angle can reach 168.9 degrees, and the temperature change range is-40 degrees to +80 degrees, so that the method is suitable for forest fire prevention monitoring, sky monitoring, ground patrol, intelligent home, airport, transformer substation monitoring and other aspects;
2) The imaging breadth is large, the imaging system can be used for 640 cores, the image surface can reach 17um, and the light quantity of the optical system is large;
3) The F number of the system is 1.2, the caliber of the whole optical lens is small, and the cost can be saved to the greatest extent;
4) The first sheet adopts germanium, so that a hard carbon film is conveniently plated; the latter three sheets use chalcogenide glass, have obvious advantage in material cost, can carry on the precision die pressing in the mass production, can reduce the processing cost, can reduce the cost effectively and raise the uniformity of the optical element;
5) The third lens adopts a diffraction surface, so that chromatic aberration and aberration generated by a broadband can be effectively corrected;
6) The maximum distortion is 84%, the distortion of the edge view field can be reduced, the relative illumination is 60%, and the radiation at normal temperature can be perceived at the edge;
7) The weight of the lens is only 18.3g, which is beneficial to light flying load;
8) The diaphragm is centered, so that stray light entering can be effectively reduced, and meanwhile, the assembly yield can be improved;
9) The optical system is composed of four mirrors, all elements are arranged on the same optical axis, and the optical system has the characteristics of wide working band, compact structure, good fitting property, good imaging quality, transfer function reaching or approaching diffraction limit and the like.
Drawings
FIG. 1 is a schematic structural view of a wide-angle lens with light weight and large flying load and heat difference elimination;
fig. 2 is an MTF graph of a light-weight flying load large-format athermal wide-angle lens at 20 ° in an embodiment of the present utility model;
FIG. 3 is an MTF curve diagram of a light-weight flying load large-format athermal wide-angle lens at-40 degrees in an embodiment of the utility model;
fig. 4 is an MTF graph of a light-weight flying load large-format athermal wide-angle lens at 80 ° in an embodiment of the present utility model;
FIG. 5 is a point column diagram of a light-weight flying load large-breadth athermal wide-angle lens at 20 degrees in an embodiment of the utility model;
FIG. 6 is a graph of curvature of field and distortion of a 20 DEG wide-angle lens with light weight and large flying load and heat difference elimination in an embodiment of the utility model;
FIG. 7 is a graph of the relative illuminance of a light-weight flying load large-format athermal wide-angle lens at 20 degrees in an embodiment of the utility model;
FIG. 8 is a tolerance analysis setting diagram of a light-weight flying load large-breadth athermal wide-angle lens in an embodiment of the utility model;
FIG. 9 is an assembly yield chart of a light-weight flying load large-breadth athermal wide-angle lens in an embodiment of the utility model;
Detailed Description
For a better understanding of the present utility model, the following examples are further illustrated, but are not limited to the following examples.
As shown in fig. 1, the light-weighted wide-angle lens with large-format athermal-effect and flight load is arranged in order from object to image along an optical axis OO': a first lens L1 having negative optical power, a second lens L2 having positive optical power, a third lens L3 having negative optical power, a fourth lens L4 having positive optical power, a double flat protection window L5, and an imaging surface S12; the convex surface of the first lens faces the object side, the convex surface of the second lens faces the object side, the concave surface of the third lens faces the object side, and the concave surface of the fourth lens faces the object side.
The first lens L1 adopts germanium, the refractive index of the germanium is as high as 4.0, aberration correction is facilitated, a hard carbon film is plated technically conveniently, and meanwhile, the spherical design is adopted on two sides, so that the lens is convenient to process; the second, third and fourth lenses use chalcogenide glass, the refractive index of the chalcogenide glass is smaller along with the temperature change coefficient dn/dT, and a good heat difference eliminating function is realized by adopting the chalcogenide glass and reasonable focal power distribution. The method has obvious advantages in material cost, can carry out precise die pressing during mass production, can reduce processing cost, and has wide market prospect.
The focal length f' of the light-weight flight load large-breadth athermal wide-angle lens system is shorter, and in order to ensure the rear working distance BFL, a reverse shooting remote structure is adopted, so that the following relational expression is satisfied:
BFL/f’>2.45；-3<f1’/f’<0；2<f5’/f’<4；-10<f1’<-5；15<f2’<20；70<f3’<75；10<f4’<15；
wherein f1' is the focal length of the first lens; f2' is the focal length of the second lens; f3' is the focal length of the third lens; f4' is the focal length of the fourth lens; f5' is the combined focal length of the second, third and fourth lenses; f' is the lens combined focal length;
from the object side to the image side, the first lens object side S1 is a spherical surface, and the first lens image side S2 is a spherical surface; the second lens object-side surface S3 is an aspheric surface, and the second lens image-side surface S4 is a spherical surface; the third lens object-side surface S6 is an aspheric surface, and the third lens image-side surface S7 is a diffraction surface; the fourth lens object-side surface S8 is an aspheric surface, the fourth lens image-side surface S9 is an aspheric surface, the double flat protection window object-side surface S10 is a plane, and the double flat protection window image-side surface S11 is a plane.
Table 1 shows the specific parameters of the present embodiment
The aspherical equation employed in table 1:
wherein the meaning of the amounts is as follows:
ZA: the aspherical surface is higher than the lens vector in the optical axis direction;
r: radius of curvature at the intersection of the surface and the optical axis OO'; y: the half caliber of the lens is vertical to the optical axis direction;
k: a conic coefficient;
A. b, C, D, E area coefficient; the specific coefficients are shown in Table 2.
TABLE 2
Table 3 use of diffraction plane coefficients in specific examples
The diffraction plane equation used in table 1 is:
Φ＝A 1 Y 2 +A 2 Y 4 +A 3 Y 6
wherein:
Φ: is the phase of the diffraction plane;
y: the half caliber of the lens is vertical to the optical axis direction;
a1, A2, A3 diffraction plane phase coefficients.
The applicable wave band of the lens is 8-14um, the F number of the optical system is equal to 1.2, the horizontal view angle is 140 degrees, the diagonal view angle is 168.9 degrees, the temperature change range is-40 degrees to +80 degrees, the lens can be used for 640 cores, and the image surface can reach 17um; the lens weight was only 18.3g.
FIGS. 2 to 4 are graphs of optical transfer functions of the lens of the present example at temperatures +20°, -40°, +80°, representing the integrated resolution level of the optical system as a function of temperature, for 30 line-to-resolution with a 640x480 17 μm detector; the long wave infrared optical system can correct various aberrations, which is enough to meet the requirement of optical passive athermalization. FIG. 5 is a 20 spot view of the lens of the present example, and it can be seen from the figure that the spot quality of the entire area is within or near the Airy spot, and a good focusing effect can be achieved for the entire area of the lens; fig. 6 is a graph of curvature of field and distortion of the lens of this example, and the graph shows that the imaging has a better degree of curvature, and the distortion is 16% lower than that of the conventional fisheye lens by 100%. Fig. 7 is a graph of the relative illumination of the present example lens at 20 deg., and it can be seen that there is a good energy distribution across the angular field of view of 168.9 deg.. FIG. 8 is a tolerance analysis setup diagram of an embodiment, from which it can be seen that the lens is provided with a lens that requires low surface profile and assembly index for mass production; fig. 9 is an assembly yield chart of a specific embodiment, and the chart shows that the primary qualification rate of the lens is very good under the condition that high index requirements are not made on the lens, and good imaging effect can be achieved without eccentric and air interval adjustment.
Claims (8)
1. A light-weight flight load large-breadth athermalization wide-angle lens is characterized in that: the lens comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from the object side to the target surface; the first lens is a negative focal power lens with a convex surface facing the object side; the second lens is a positive focal power lens with a convex surface facing the object side; the third lens is a positive focal power lens with a concave surface facing the object side; the fourth lens is a positive focal power lens with a concave surface facing the object side;
the following relation is satisfied: BFL/f' >2.45; -3< f1'/f' <0; wherein BFL is the back focal length, f1 'is the focal length of the first lens, and f' is the lens assembly focal length.
2. The lightweight flying load large format athermal wide angle lens of claim 1, wherein: the following relation is satisfied: 2< f5'/f' <4; -10< f1' < -5;15< f2' <20;70< f3' <75;10< f4' <15; wherein f1' is the focal length of the first lens; f2' is the focal length of the second lens; f3' is the focal length of the third lens; f4' is the focal length of the fourth lens; f5' is the combined focal length of the second lens, the third lens and the fourth lens; f' is the lens combined focal length.
3. The lightweight flying load large-format athermal wide-angle lens of claim 1 or 2, wherein: the material used for the first lens is germanium; the materials used for the second lens, the third lens and the fourth lens are all chalcogenide glass.
4. The lightweight flying load large-format athermal wide-angle lens of claim 1 or 2, wherein: the center thickness of the first lens is 2+/-0.002 mm; the center thickness of the second lens is 2+/-0.002 mm; the center thickness of the third lens is 2.5+/-0.002 mm; the center thickness of the fourth lens is 3.7.+ -. 0.002mm.
5. The lightweight flying load large-format athermal wide-angle lens of claim 1 or 2, wherein: the center interval between the first lens and the second lens is 13.533 plus or minus 0.002mm; the center spacing between the second lens and the third lens is 0.469 + -0.002 mm; the center spacing between the third lens and the fourth lens is 5±0.002mm.
6. The lightweight flying load large-format athermal wide-angle lens of claim 1 or 2, wherein: the object side surface of the first lens is a spherical surface, and the image side surface of the first lens is a spherical surface; the object side surface of the second lens is an aspheric surface, and the image side surface of the second lens is a spherical surface; the object side surface of the third lens is an aspheric surface, and the image side surface of the third lens is a diffraction surface; the fourth lens element has an aspheric object-side surface and an image-side surface.
7. The lightweight flying load large-format athermal wide-angle lens of claim 1 or 2, wherein: the curvature radius of the object side surface of the first lens is-1.39+/-0.002 mm, and the curvature radius of the image side surface of the first lens is-0.84+/-0.002 mm; the curvature radius of the object side surface of the second lens is 1.28 plus or minus 0.002mm, and the curvature radius of the image side surface of the second lens is 4.23 plus or minus 0.002mm; the curvature radius of the object side surface of the third lens is-0.26+/-0.002 mm, and the curvature radius of the image side surface of the third lens is-0.26+/-0.002 mm; the radius of curvature of the object side of the fourth lens is-3.17+/-0.002 mm, and the radius of curvature of the image side of the fourth lens is 1.24+/-0.002 mm.
8. The lightweight flying load large-format athermal wide-angle lens of claim 1 or 2, wherein: the applicable wave band is 8-14um, the F number of the optical system is equal to 1.2, the horizontal view angle is 140 degrees, the diagonal view angle is 168.9 degrees, and the temperature change range is-40 degrees to +80 degrees.
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| CN202320673889.4U CN219657942U (en) | 2023-03-30 | 2023-03-30 | Light-weight wide-angle lens with large flying load and large athermal aberration |
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| CN202320673889.4U CN219657942U (en) | 2023-03-30 | 2023-03-30 | Light-weight wide-angle lens with large flying load and large athermal aberration |
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