CN215895098U - Miniature fisheye imaging lens - Google Patents
Miniature fisheye imaging lens Download PDFInfo
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- CN215895098U CN215895098U CN202122446367.4U CN202122446367U CN215895098U CN 215895098 U CN215895098 U CN 215895098U CN 202122446367 U CN202122446367 U CN 202122446367U CN 215895098 U CN215895098 U CN 215895098U
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Abstract
The utility model discloses a micro fish-eye imaging lens, which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from an object side to an image side along an optical axis, wherein the first lens to the sixth lens respectively comprise an object side surface facing the object side and allowing imaging light rays to pass through and an image side surface facing the image side and allowing the imaging light rays to pass through; the first lens element has negative refractive index, the second lens element has positive refractive index, the third lens element has negative refractive index, the fourth lens element has positive refractive index, the fifth lens element has positive refractive index, the sixth lens element has positive refractive index, and the optical imaging lens assembly has only the above six lens elements with refractive index. The six lenses are adopted along the direction from the object side to the image side, the color reducibility of the lens is high through the arrangement design of the refractive index and the surface type of each lens, no obvious blue-violet edge exists, meanwhile, the lens adopts the design of 200 ten thousand pixels, the ultrahigh-definition imaging effect is achieved, and the imaging picture is clear and uniform.
Description
Technical Field
The utility model relates to the technical field of lenses, in particular to a micro fisheye imaging lens.
Background
The fish-eye lens is a lens with a focal length of 16mm or shorter and a visual angle close to or equal to 180 degrees, the front lens of the lens is large in diameter and is in a parabolic shape and protrudes towards the front part of the lens, and the fish-eye lens is quite similar to the fish eyes, so the fish-eye lens is commonly called as the fish-eye lens, and the fish-eye lens is widely applied to the fields of VR cameras, security monitoring, video conferences, unmanned aerial vehicles, vehicles and the like at present, so the requirements on the fish-eye lens are higher and higher. However, the existing 8mm fish-eye lens has at least the following defects:
1. most of existing 8mm fisheye lenses are insufficient in blue-violet edge correction, and blue-violet edge chromatic aberration can occur at the edge of a view field or the edge of light-dark contrast in the view field, so that imaging quality is affected.
2. The existing 8mm fisheye lens has high tolerance sensitivity and is not easy to manufacture.
3. The existing 8mm fisheye lens is unstable in temperature drift, easy to run burnt in high and low temperature environments, and influences practical use.
SUMMERY OF THE UTILITY MODEL
The present invention is directed to a micro fisheye imaging lens, which solves at least one of the above problems.
In order to achieve the purpose, the utility model adopts the following technical scheme:
a micro fisheye imaging lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from an object side to an image side along an optical axis, wherein the first lens to the sixth lens respectively comprise an object side surface facing the object side and allowing imaging light rays to pass and an image side surface facing the image side and allowing the imaging light rays to pass;
the first lens element with negative refractive index has a convex object-side surface and a concave image-side surface;
the second lens element with positive refractive index has a convex object-side surface and a convex image-side surface;
the third lens element with negative refractive index has a concave object-side surface and a concave image-side surface;
the fourth lens element with positive refractive index has a concave object-side surface and a convex image-side surface;
the fifth lens element with positive refractive index has a convex object-side surface and a convex image-side surface;
the sixth lens element with positive refractive index has a concave object-side surface and a convex image-side surface;
the optical imaging lens only has the six lenses with the refractive indexes, and meets the following conditional expression:
-3＜(f1/f)＜-2，0.8＜(f2/f)＜1.8，-2＜(f3/f)＜-1，
4＜(f4/f)＜2，6＜(f5/f)＜7，-21＜(f6/f)＜-20，
wherein f is a focal length value of the lens, and f1, f2, f3, f4, f5 and f6 are focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens, respectively.
Preferably, the lens complies with the following conditional expression: 0.74 < | RD2/RD4| < 1.1, where RD2 is the value of the radius of curvature of the image-side surface of the first lens and RD4 is the value of the radius of curvature of the image-side surface of the second lens.
Preferably, the lens further includes a diaphragm disposed between the first lens and the second lens, and an image side surface of the second lens is cemented with an object side surface of the third lens.
Preferably, the lens complies with the following conditional expression: vd5-Vd4 > 30, wherein Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens.
Preferably, the lens complies with the following conditional expression: -0.9 < f4/f5 < -0.6.
Preferably, the temperature coefficient of refractive index dn/dt of the fifth lens is a negative value.
Preferably, the image side surface of the fifth lens and the object side surface of the sixth lens are mutually cemented, and the following conditional expression is satisfied: vd5-Vd6 > 30, wherein Vd5 is the Abbe number of the fifth lens and Vd6 is the Abbe number of the sixth lens.
Preferably, the lens complies with the following conditional expression: TTL is less than 23mm, wherein TTL is the distance between the object side surface of the first lens and the imaging surface on the optical axis.
After adopting the technical scheme, compared with the background technology, the utility model has the following advantages:
1. the six lenses are adopted along the direction from the object side to the image side, the color reducibility of the lens is high through the arrangement design of the refractive index and the surface type of each lens, no obvious blue-violet edge exists, meanwhile, the lens adopts the design of 200 ten thousand pixels, the ultrahigh-definition imaging effect is achieved, and the imaging picture is clear and uniform.
2. The image side surfaces of the first lens and the second lens have basically the same curvature radius, so that the light spherical aberration and other high-order aberration can be reasonably distributed, the tolerance sensitivity of the two groups of lenses can be further reduced, and the lenses can be more conveniently manufactured.
3. The refractive index temperature coefficient dn/dt of the fifth lens is a negative value, the fifth lens can effectively balance temperature drift, no thermalization is realized, and the lens has small temperature drift amount and is not easy to defocus when working in a high-temperature and low-temperature environment.
4. The light transmission F/1.8 of the utility model has the imaging edge illumination greater than 50%, and ensures that the utility model can have good picture brightness when used in a weak light environment.
Drawings
FIG. 1 is a light path diagram according to the first embodiment;
FIG. 2 is a graph of MTF of the lens in the first embodiment under the visible light of 435nm-656 nm;
FIG. 3 is a defocus graph of the lens in the first embodiment under 435-656 nm of visible light;
FIG. 4 is a graph of lateral chromatic aberration of the lens in the first embodiment under the condition of 435nm-656nm of visible light;
FIG. 5 is a graph of longitudinal chromatic aberration of the lens in the first embodiment under 435nm-656nm of visible light;
FIG. 6 is a graph of relative illumination at 546nm for a lens according to one embodiment;
FIG. 7 is a light path diagram of the second embodiment;
FIG. 8 is a graph of MTF of the lens of the second embodiment in the visible light range from 435nm to 656 nm;
FIG. 9 is a defocus graph of the lens in the second embodiment in the visible light range from 435nm to 656 nm;
FIG. 10 is a lateral chromatic aberration curve of the lens of the second embodiment under the visible light of 435nm-656 nm;
FIG. 11 is a graph of longitudinal chromatic aberration of the lens of the second embodiment in the visible light range from 435nm to 656 nm;
FIG. 12 is a graph of relative illumination at 546nm for the lens of the second embodiment;
FIG. 13 is a light path diagram of the third embodiment;
FIG. 14 is a graph of MTF of the lens of the third embodiment in the visible light range from 435nm to 656 nm;
FIG. 15 is a defocus graph of the lens in the third embodiment in the visible light range from 435nm to 656 nm;
FIG. 16 is a graph of lateral chromatic aberration of the lens of the third embodiment in the visible light range from 435nm to 656 nm;
FIG. 17 is a graph of longitudinal chromatic aberration of the lens of the third embodiment in the visible light range from 435nm to 656 nm;
FIG. 18 is a graph of relative illumination at 546nm for a lens according to the third embodiment;
FIG. 19 is a light path diagram of the fourth embodiment;
FIG. 20 is a graph showing the MTF curves of the lens of the fourth embodiment in the visible light range from 435nm to 656 nm;
FIG. 21 is a graph showing the defocus curves of the lens in the fourth embodiment in the visible light range from 435nm to 656 nm;
FIG. 22 is a graph of lateral chromatic aberration of the lens of the fourth embodiment in the visible light range from 435nm to 656 nm;
FIG. 23 is a graph of longitudinal chromatic aberration of the lens of the fourth embodiment in the visible light range from 435nm to 656 nm;
FIG. 24 is a graph of relative illumination at 546nm for the lens of the fourth embodiment.
Description of reference numerals:
the lens comprises a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, an aperture 7 and a protective glass 8.
Detailed Description
To further illustrate the various embodiments, the utility model provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the utility model and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.
The utility model will now be further described with reference to the accompanying drawings and detailed description.
In the present specification, the term "a lens element having a positive refractive index (or a negative refractive index)" means that the paraxial refractive index of the lens element calculated by the gauss theory is positive (or negative). The term "object-side (or image-side) of a lens" is defined as the specific range of imaging light rays passing through the lens surface. The determination of the surface shape of the lens can be performed by the judgment method of a person skilled in the art, i.e., by the sign of the curvature radius (abbreviated as R value). The R value may be commonly used in optical design software, such as Zemax or CodeV. The R value is also commonly found in lens data sheets (lens sheets) of optical design software. When the R value is positive, the object side is judged to be a convex surface; and when the R value is negative, judging that the object side surface is a concave surface. On the contrary, regarding the image side surface, when the R value is positive, the image side surface is judged to be a concave surface; when the R value is negative, the image side surface is judged to be convex.
The utility model discloses a micro fish-eye imaging lens, which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from an object side to an image side along an optical axis, wherein the first lens to the sixth lens respectively comprise an object side surface facing the object side and allowing imaging light rays to pass through and an image side surface facing the image side and allowing the imaging light rays to pass through;
the first lens element with negative refractive index has a convex object-side surface and a concave image-side surface;
the second lens element with positive refractive index has a convex object-side surface and a convex image-side surface;
the third lens element with negative refractive index has a concave object-side surface and a concave image-side surface;
the fourth lens element with positive refractive index has a concave object-side surface and a convex image-side surface;
the fifth lens element with positive refractive index has a convex object-side surface and a convex image-side surface;
the sixth lens element with positive refractive index has a concave object-side surface and a convex image-side surface;
the optical imaging lens only has the six lenses with the refractive indexes, and meets the following conditional expression:
-3＜(f1/f)＜-2，0.8＜(f2/f)＜1.8，-2＜(f3/f)＜-1，
4＜(f4/f)＜2，6＜(f5/f)＜7，-21＜(f6/f)＜-20，
wherein f is a focal length value of the lens, and f1, f2, f3, f4, f5 and f6 are focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens, respectively.
Preferably, the lens complies with the following conditional expression: 0.74 < | RD2/RD4| < 1.1, wherein RD2 is the curvature radius value of the image side surface of the first lens, RD4 is the curvature radius value of the image side surface of the second lens, and when the image side surfaces of the two lenses have basically the same curvature radius, the spherical aberration and other high-order aberrations of the rays can be reasonably distributed, thereby reducing the tolerance sensitivity of the two groups of lenses.
Preferably, the lens further includes a diaphragm disposed between the first lens and the second lens, and an image side surface of the second lens is cemented with an object side surface of the third lens.
Preferably, the lens complies with the following conditional expression: vd5-Vd4 > 30, wherein Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens.
Preferably, the lens complies with the following conditional expression: f4/f5 is more than-0.9 and less than-0.6, and the ratio of the optical powers of the fourth lens and the fifth lens is reasonably distributed, so that the on-axis chromatic aberration and the off-axis chromatic aberration of the lens can be well corrected, and the image quality is improved.
Preferably, the temperature coefficient dn/dt of the refractive index of the fifth lens is a negative value, that is, the refractive index of the material decreases with the increase of the temperature, and the fifth lens can offset the influence of the temperature change on the back focal shift of the lens, so as to effectively balance the temperature drift and prevent the thermal defocusing phenomenon from occurring easily.
Preferably, the image side surface of the fifth lens and the object side surface of the sixth lens are mutually cemented, and the following conditional expression is satisfied: vd5-Vd6 is more than 30, Vd5 is the abbe number of the fifth lens, Vd6 is the abbe number of the sixth lens, and the fifth lens and the sixth lens are combined by high-low dispersion materials, so that chromatic aberration can be corrected conveniently, and the system performance can be improved.
Preferably, the lens complies with the following conditional expression: TTL is less than 23mm, wherein TTL is the distance between the object side surface of the first lens and the imaging surface on the optical axis.
The micro fisheye imaging lens of the utility model will be described in detail with specific embodiments.
Example one
Referring to fig. 1, the present embodiment discloses a micro fisheye imaging lens, which includes, in order along an optical axis, a first lens element 1, a second lens element 2, a third lens element 3, a fourth lens element 4, a fifth lens element 5, and a sixth lens element 6 from an object side a1 to an image side a2, wherein the first lens element 1 to the sixth lens element 6 each include an object side surface facing the object side a1 and allowing an imaging light to pass therethrough, and an image side surface facing the image side a2 and allowing the imaging light to pass therethrough;
the first lens element 1 has a negative refractive index, and the object-side surface and the image-side surface of the first lens element 1 are convex and concave;
the second lens element 2 has a positive refractive index, and the object-side surface and the image-side surface of the second lens element 2 are convex and convex;
the third lens element 3 has a negative refractive index, and the object-side surface and the image-side surface of the third lens element 3 are concave;
the fourth lens element 4 has a positive refractive index, and the object-side surface and the image-side surface of the fourth lens element 4 are concave and convex, respectively;
the fifth lens element 5 has a positive refractive index, and the object-side surface and the image-side surface of the fifth lens element 5 are convex and convex;
the sixth lens element 6 has a positive refractive index, and the sixth lens element 6 has a concave object-side surface and a convex image-side surface;
the optical imaging lens only has the six lenses with the refractive indexes, and meets the following conditional expression:
-3＜(f1/f)＜-2，0.8＜(f2/f)＜1.8，-2＜(f3/f)＜-1，
4＜(f4/f)＜2，6＜(f5/f)＜7，-21＜(f6/f)＜-20，
wherein f is a focal length value of the lens, and f1, f2, f3, f4, f5 and f6 are focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens, respectively.
In this embodiment, the diaphragm 7 is disposed between the first lens 1 and the second lens 2, but in other embodiments, the diaphragm 7 may be disposed at another suitable position, the image-side surface of the second lens 2 is cemented with the object-side surface of the third lens 3, and the image-side surface of the fifth lens 5 is cemented with the object-side surface of the sixth lens 6.
Detailed optical data of this embodiment are shown in table 1.
Table 1 detailed optical data of example one
In this embodiment, the lens is suitable for a 1/2.7 "sensor, the focal length of the lens is F equal to 7.5mm, F/1.8, the field angle DFOV is about 110 °, and the total length TTL is 22.9 mm.
Fig. 1 is a schematic diagram of an optical path of an optical imaging lens in this embodiment. Please refer to fig. 2, which shows that when the spatial frequency of the lens reaches 100lp/mm, the full-field transfer function image is still greater than 40%, the center-to-edge uniformity is high, the imaging quality is excellent, and the resolution of the lens is high. Referring to fig. 3, the defocus graph of the lens under 435nm-656nm visible light shows that the defocus amount of the lens under visible light is small. Please refer to fig. 4, which shows that, in a wide spectrum band of 435nm to 656nm, the latercolor is less than 5um, which ensures that blue edge or red edge of the projection image does not occur, and has high image color reducibility. Please refer to fig. 5, which shows that the axial chromatic aberration is less than ± 0.06mm, the color reduction is good, the chromatic aberration is small, and the blue-violet edge phenomenon is not obvious. Referring to fig. 6, it can be seen that the relative illuminance of the lens under the 546nm of visible light is greater than 50%, which provides more uniform illuminance for the image plane and ensures that the relative illuminance is uniform under the large-light-passing and large-angle conditions.
Example two
As shown in fig. 7 to 12, the surface convexo-concave shape and the refractive index of each lens of the present embodiment are substantially the same as those of the first embodiment, and the optical parameters such as the curvature radius of the surface of each lens and the thickness of the lens are different.
The detailed optical data of this embodiment are shown in table 2.
Table 2 detailed optical data of example two
| Surface of | Type (B) | Caliber size (diameter) | Radius of curvature | Thickness of | Material of | Refractive index | Coefficient of dispersion | Focal length | |
| OBJ | Shot object surface | 0.00 | | Infinity | |||||
| 1 | First lens | 7.60 | 7.399952 | 1.3 | H-LAK52 | 1.729164 | 54.669031 | -12.243927 | |
| 2 | 5.14 | 3.753107 | 2.429864 | ||||||
| STO | 4.45 | |
0 | ||||||
| 4 | Second lens | 5.05 | 5.960162 | 1.5 | H-ZLAF68N | 1.883001 | 39.225276 | 4.833333 | |
| 5 | Third lens | 5.05 | -13.5387 | 0.6 | H-ZBAF20 | 1.701545 | 41.140848 | -6.514467 | |
| 6 | 4.23 | 7.08703 | 0.82 | ||||||
| 7 | Fourth lens | 4.24 | -5.719699 | 3.39 | H-ZLAF68N | 1.883001 | 39.225276 | 23.0917 | |
| 8 | 6.69 | -5.719699 | 0.1 | ||||||
| 9 | Fifth lens element | 5.72 | 8.357298 | 2.45 | H-ZPK5 | 1.592807 | 68.525033 | 5.220002 | |
| 10 | Sixth lens element | 5.72 | -4.400914 | 3.2 | H-ZF12 | 1.761823 | 26.613203 | -8.483314 | |
| 11 | 6.86 | -17.81848 | 0.5 | ||||||
| 12 | Cover glass | 5.79 | Infinity | 0.3 | H-K9L | 1.516797 | 64.212351 | Infinity | |
| 13 | 5.82 | Infinity | 5.868408 | ||||||
| 14 | 6.84 | Infinity | 0.4 | H-K9L | 1.516797 | 64.212351 | Infinity | ||
| 15 | 6.89 | Infinity | 0.125 | ||||||
| IMA | Image plane | 6.91 | Infinity |
In this embodiment, the lens is suitable for a 1/2.7 "sensor, the focal length of the lens is F equal to 7.5mm, F/1.8, the field angle DFOV is about 110 °, and the total length TTL is 22.9 mm.
Fig. 7 is a schematic diagram of an optical path of an optical imaging lens in this embodiment. Please refer to fig. 8, which shows that when the spatial frequency of the lens reaches 100lp/mm, the full-field transfer function image is still greater than 40%, the center-to-edge uniformity is high, the imaging quality is excellent, and the resolution of the lens is high. Please refer to fig. 9, which shows the defocus curve of the lens in 435nm-656nm of visible light, and it can be seen that the defocus amount of the lens in visible light is small. Please refer to fig. 10, which shows that, in a wide spectrum band of 435nm to 656nm, the latercolor is less than 5um, which ensures that blue edge or red edge of the projection image does not occur, and has high image color reducibility. Please refer to fig. 11, which shows that the axial chromatic aberration is less than ± 0.06mm, the color reduction is good, the chromatic aberration is small, and the blue-violet edge phenomenon is not obvious. Referring to fig. 12, it can be seen that the relative illuminance of the lens under the visible light 546nm is greater than 50%, which provides more uniform illuminance for the image plane and ensures that the relative illuminance is uniform under the condition of large light flux and large angle.
EXAMPLE III
As shown in fig. 13 to 18, the surface convexoconcave and the refractive index of each lens of the present embodiment are substantially the same as those of the first embodiment, and the optical parameters such as the curvature radius of the surface of each lens and the thickness of the lens are different.
The detailed optical data of this embodiment are shown in table 3.
Table 3 detailed optical data of example three
| Surface of | Type (B) | Caliber size (diameter) | Radius of curvature | Thickness of | Material of | Refractive index | Coefficient of dispersion | Focal length | |
| OBJ | Shot object surface | 0.00 | | Infinity | |||||
| 1 | First lens | 7.60 | 7.399952 | 1.3 | H-LAK52 | 1.729164 | 54.669031 | -12.364846 | |
| 2 | 5.35 | 3.769767 | 2.827443 | ||||||
| STO | 4.53 | |
0 | ||||||
| 4 | Second lens | 5.01 | 6.170015 | 1.9 | H-ZLAF68N | 1.883001 | 39.225276 | 6.016829 | |
| 5 | Third lens | 5.01 | -34.18672 | 0.6 | H-ZBAF20 | 1.701545 | 41.140848 | -8.041729 | |
| 6 | 4.26 | 6.852831 | 0.9 | ||||||
| 7 | Fourth lens | 4.27 | -5.684764 | 2.759884 | H-ZLAF68N | 1.883001 | 39.225276 | 22.286031 | |
| 8 | 6.69 | -5.425302 | 0.1 | ||||||
| 9 | Fifth lens element | 5.72 | 8.03204 | 2.45 | H-ZPK5 | 1.592807 | 68.525033 | 5.115019 | |
| 10 | Sixth lens element | 5.72 | -4.341185 | 2.697218 | H-ZF12 | 1.761823 | 26.613203 | -8.563453 | |
| 11 | 6.86 | -16.19554 | 0.5 | ||||||
| 12 | Cover glass | 5.75 | Infinity | 0.3 | H-K9L | 1.516797 | 64.212351 | Infinity | |
| 13 | 5.79 | Infinity | 6.130573 | ||||||
| 14 | 6.90 | Infinity | 0.4 | H-K9L | 1.516797 | 64.212351 | Infinity | ||
| 15 | 6.95 | Infinity | 0.125 | ||||||
| IMA | Image plane | 6.98 | Infinity |
In this embodiment, the lens is suitable for a 1/2.7 "sensor, the focal length of the lens is F equal to 7.5mm, F/1.8, the field angle DFOV is about 110 °, and the total length TTL is 22.9 mm.
Fig. 13 is a schematic diagram of an optical path of an optical imaging lens in this embodiment. Please refer to fig. 14, which shows the MTF curve under 435nm-656nm, when the spatial frequency of the lens reaches 100lp/mm, the full-field transfer function image is still greater than 40%, the center-to-edge uniformity is high, the imaging quality is good, and the resolution of the lens is high. Please refer to fig. 15, which shows the defocus curve of the lens under 435nm-656nm of visible light, and it can be seen that the defocus amount of the lens under visible light is small. Please refer to fig. 16, which shows that, in a wide spectrum band of 435nm to 656nm, the latercolor is less than 5um, which ensures that blue edge or red edge of the projection image does not occur, and has high image color reducibility. Please refer to fig. 17 for a longitudinal chromatic aberration curve of the lens under 435nm-656nm of visible light, and it can be seen from the graph that the axial chromatic aberration is less than ± 0.06mm, the color restoration is good, the chromatic aberration is small, and the blue-violet edge phenomenon is not obvious. Referring to fig. 18, it can be seen that the relative illuminance of the lens under the visible light 546nm is greater than 50%, which provides more uniform illuminance for the image plane and ensures that the relative illuminance is uniform under the condition of large light flux and large angle.
Example four
As shown in fig. 19 to 24, the surface convexoconcave and the refractive index of each lens of the present embodiment are substantially the same as those of the first embodiment, and the optical parameters such as the curvature radius of the surface of each lens and the thickness of the lens are different.
The detailed optical data of this embodiment are shown in table 4.
Table 4 detailed optical data for example four
| Surface of | Type (B) | Caliber size (diameter) | Radius of curvature | Thickness of | Material of | Refractive index | Coefficient of dispersion | Focal length | |
| OBJ | Shot object surface | 0.00 | | Infinity | |||||
| 1 | First lens | 7.60 | 7.399952 | 1.3 | H-LAK52 | 1.729164 | 54.669031 | -12.243985 | |
| 2 | 5.14 | 3.753107 | 2.429864 | ||||||
| 3 | 4.45 | |
0 | ||||||
| 4 | Second lens | 5.05 | 5.960162 | 1.5 | H-ZLAF68N | 1.883001 | 39.225276 | 4.833338 | |
| 5 | Third lens | 5.05 | -13.5387 | 0.6 | H-ZBAF20 | 1.701545 | 41.140848 | -6.514484 | |
| 6 | 4.23 | 7.08703 | 0.82 | ||||||
| STO | Fourth lens | 4.24 | -5.719699 | 3.39 | H-ZLAF68N | 1.883001 | 39.225276 | 23.091737 | |
| 8 | 6.69 | -5.719699 | 0.1 | ||||||
| 9 | Fifth lens element | 5.72 | 8.357298 | 2.45 | H-ZPK5 | 1.592807 | 68.525033 | 5.220008 | |
| 10 | Sixth lens element | 5.72 | -4.400914 | 3.2 | H-ZF12 | 1.761823 | 26.613203 | -8.483309 | |
| 11 | 6.86 | -17.81848 | 0.5 | ||||||
| 12 | Cover glass | 5.79 | Infinity | 0.3 | H-K9L | 1.516797 | 64.212351 | Infinity | |
| 13 | 5.82 | Infinity | 5.868408 | ||||||
| 14 | 6.84 | Infinity | 0.4 | H-K9L | 1.516797 | 64.212351 | Infinity | ||
| 15 | 6.89 | Infinity | 0.125 | ||||||
| IMA | Image plane | 6.91 | Infinity |
In this embodiment, the lens is suitable for a 1/2.7 "sensor, the focal length of the lens is F equal to 7.5mm, F/1.8, the field angle DFOV is about 110 °, and the total length TTL is 22.9 mm.
Fig. 19 is a schematic diagram of an optical path of an optical imaging lens in this embodiment. Please refer to fig. 20, which shows that when the spatial frequency of the lens reaches 100lp/mm, the full-field transfer function image is still larger than 38%, the center-to-edge uniformity is high, the imaging quality is excellent, and the resolution of the lens is high. Please refer to fig. 21, which shows the defocus curve of the lens in the visible light of 435nm-656nm, and it can be seen that the defocus amount of the lens in the visible light is small. Please refer to fig. 22, which shows that, in a wide spectrum band of 435nm to 656nm, the latercolor is less than 5um, which ensures that blue edge or red edge of the projection image does not occur, and has high image color reducibility. Please refer to fig. 23 for a longitudinal chromatic aberration curve of the lens under 435nm-656nm of visible light, and it can be seen from the graph that the axial chromatic aberration is less than ± 0.07mm, the color reduction is good, the chromatic aberration is small, and the blue-violet edge phenomenon is not obvious. Referring to fig. 24, it can be seen that the relative illuminance of the lens under the visible light 546nm is greater than 50%, which provides more uniform illuminance for the image plane and ensures that the relative illuminance is uniform under the condition of large light flux and large angle.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. The micro fisheye imaging lens is characterized by sequentially comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from an object side to an image side along an optical axis, wherein the first lens to the sixth lens respectively comprise an object side surface facing the object side and allowing imaging light rays to pass through and an image side surface facing the image side and allowing the imaging light rays to pass through;
the first lens element with negative refractive index has a convex object-side surface and a concave image-side surface;
the second lens element with positive refractive index has a convex object-side surface and a convex image-side surface;
the third lens element with negative refractive index has a concave object-side surface and a concave image-side surface;
the fourth lens element with positive refractive index has a concave object-side surface and a convex image-side surface;
the fifth lens element with positive refractive index has a convex object-side surface and a convex image-side surface;
the sixth lens element with positive refractive index has a concave object-side surface and a convex image-side surface;
the optical imaging lens only has the six lenses with the refractive indexes, and meets the following conditional expression:
-3＜(f1/f)＜-2，0.8＜(f2/f)＜1.8，-2＜(f3/f)＜-1，
4＜(f4/f)＜2，6＜(f5/f)＜7，-21＜(f6/f)＜-20，
wherein f is a focal length value of the lens, and f1, f2, f3, f4, f5 and f6 are focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens, respectively.
2. The micro fisheye imaging lens of claim 1, wherein the following condition is satisfied: 0.74 < | RD2/RD4| < 1.1, where RD2 is the value of the radius of curvature of the image-side surface of the first lens and RD4 is the value of the radius of curvature of the image-side surface of the second lens.
3. The micro fisheye imaging lens of claim 1, further comprising an aperture stop disposed between the first lens element and the second lens element, wherein the image side surface of the second lens element is cemented to the object side surface of the third lens element.
4. The micro fisheye imaging lens of claim 1, wherein the following condition is satisfied: vd5-Vd4 > 30, wherein Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens.
5. The micro fisheye imaging lens of claim 1, wherein the following condition is satisfied: -0.9 < f4/f5 < -0.6.
6. The micro fisheye imaging lens of claim 1, wherein the temperature coefficient of refractive index dn/dt of the fifth lens is negative.
7. The micro fisheye imaging lens of claim 1, wherein the image side surface of the fifth lens element and the object side surface of the sixth lens element are cemented together, and the following conditional expressions are satisfied: vd5-Vd6 > 30, wherein Vd5 is the Abbe number of the fifth lens and Vd6 is the Abbe number of the sixth lens.
8. The micro fisheye imaging lens of claim 1, wherein the following condition is satisfied: TTL is less than 23mm, wherein TTL is the distance between the object side surface of the first lens and the imaging surface on the optical axis.
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