CN212781469U - Day and night confocal security lens - Google Patents
Day and night confocal security lens Download PDFInfo
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- CN212781469U CN212781469U CN202021809774.6U CN202021809774U CN212781469U CN 212781469 U CN212781469 U CN 212781469U CN 202021809774 U CN202021809774 U CN 202021809774U CN 212781469 U CN212781469 U CN 212781469U
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Abstract
The utility model discloses a day and night confocal security lens, which comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5 which are sequentially arranged along the incident direction of light, wherein the first lens L1 is a negative focal power convex-concave spherical lens; the second lens L2 is a positive power concave-convex aspheric lens; the third lens L3 is a positive focal power biconvex spherical lens; the fourth lens L4 is a negative power meniscus aspherical lens; the fifth lens L5 is a positive power biconvex aspherical lens; each lens comprises at least one lens with low refractive index and high dispersion rate, and the conditions are met: 1.437< nd <1.496, 81.6< vd < 95.1. The lens can realize day and night confocal, avoids blue and purple edges in visible light, has high imaging quality, solves the problem of optimized balance between high and low temperature focus drift and normal temperature resolving power, and does not generate virtual focus at high and low temperatures.
Description
Technical Field
The utility model belongs to the technical field of optical lens, concretely relates to confocal security protection camera lens of day night.
Background
The national attention and attention to the technology in the security monitoring field causes the booming of enterprises in the security monitoring field, and lens manufacturers intervene in security monitoring products, so that the competition is increasingly violent, and the competitiveness can be formed only by continuously developing lenses with high cost performance. The following defects generally exist in the existing monitoring lens: the lens has the problems of large focus drift amount in visible light and near infrared light bands, blue-violet edge phenomenon, low definition, high and low temperature virtual focus, more noise points and the like, and the requirements of day and night confocal and clear imaging are difficult to achieve.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to the above-mentioned problem, provide a confocal security protection camera lens of day night, make the camera lens reduce greatly at the focus drift volume of visible light and near-infrared light wave band, realize that the day night is confocal to alleviate the phenomenon of blue purple limit in the visible light, and improve imaging quality through revising each lens aberration, solved the optimization balance problem between high and low temperature focus drift and the normal atmospheric temperature analytic power, high and low temperature is not virtual burnt.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
the utility model provides a confocal security protection camera lens of day night, include first lens L1, second lens L2, third lens L3, fourth lens L4 and fifth lens L5 that set gradually along light incident direction, wherein:
the first lens L1 is a concave-convex spherical lens with negative focal power;
the second lens L2 is a positive power concave-convex aspheric lens;
the third lens L3 is a positive focal power biconvex spherical lens;
the fourth lens L4 is a negative power meniscus aspherical lens;
the fifth lens L5 is a positive power biconvex aspherical lens;
each lens comprises at least one lens with low refractive index and high dispersion rate, and the conditions are met:
1.437<nd<1.496，81.6<vd<95.1
where nd is the refractive index of the lens under d light, and vd is the dispersion coefficient of the lens under d light.
Preferably, the lens with low refractive index and high dispersion ratio is the first lens L1 or the third lens L3.
Preferably, the day and night confocal security lens meets the conditions:
0.17<f/TTL<0.32
wherein f is the focal length of the lens in mm, and TTL is the total optical length of the lens in mm.
Preferably, the total optical length TTL of the lens is less than or equal to 22 mm.
Preferably, the aspheric lens satisfies the following equation:
wherein Z is rise, c is reciprocal of curvature radius, y is radial coordinate, k is conic coefficient, A4、A6、A8、A10、A12、A14、A16、A18Are aspheric high order coefficients.
Preferably, the day and night confocal security lens further comprises a diaphragm, and the diaphragm is arranged between the first lens L1 and the second lens L2.
Preferably, the day and night confocal security lens further comprises an optical filter IRCUT and protective glass, wherein the optical filter IRCUT is arranged between the fifth lens L5 and the image plane, and the optical filter IRCUT is close to the fifth lens L5.
Compared with the prior art, the beneficial effects of the utility model are that:
1) at least one lens with low refractive index and high dispersion ratio is adopted, and the focal power of each lens is reasonably distributed, so that the focus drift of the lens in visible light and near infrared light bands is greatly reduced, day and night confocal is realized, the phenomenon of blue-purple edge in visible light is reduced, and the imaging definition and color authenticity are improved;
2) the aspheric lens is adopted to correct aberration, so that the imaging quality of the lens is improved, the problem of optimized balance between high and low temperature focus drift and normal temperature resolving power is solved, and the high and low temperatures are free of virtual focus;
3) by adopting the lens with the 2G3P structure, the cost can be greatly reduced and the economic benefit can be improved when the lens is produced on a large scale.
Drawings
Fig. 1 is a schematic structural view of the present invention;
FIG. 2 is a visible light MTF diagram of the present invention;
FIG. 3 is a near infrared MTF chart of the present invention;
FIG. 4 is a-40 degree MTF plot of the present invention;
fig. 5 is an 80 degree MTF graph according to the present invention.
Detailed Description
The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and examples, and the following examples do not limit the present invention.
The symbols used in the specification of the present application are defined as follows: nd is the refractive index of the lens under d light, and vd is the dispersion coefficient of the lens under d light; f is the focal length of the lens in mm; f # is the lens F-number; TTL is the total optical length of the lens in mm; the lens surfaces of the lenses are numbered in sequence from the light incidence direction (i.e., from the object plane to the image plane), L1R1 is the first surface of the first lens L1, L1R2 is the second surface of the first lens L1, L2R1 is the first surface of the second lens L2, L2R2 is the second surface of the second lens L2, L3R1 is the first surface of the third lens L3, L3R2 is the second surface of the third lens L3, L4R1 is the first surface of the fourth lens L4, L4R2 is the second surface of the fourth lens L4, L5R1 is the first surface of the fifth lens L5, and L5R2 is the second surface of the fifth lens L5.
As shown in fig. 1 to 5, a day and night confocal security lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5, which are sequentially arranged along a light incidence direction, wherein:
the first lens L1 is a concave-convex spherical lens with negative focal power;
the second lens L2 is a positive power concave-convex aspheric lens;
the third lens L3 is a positive focal power biconvex spherical lens;
the fourth lens L4 is a negative power meniscus aspherical lens;
the fifth lens L5 is a positive power biconvex aspherical lens;
each lens comprises at least one lens with low refractive index and high dispersion rate, and the conditions are met:
1.437<nd<1.496，81.6<vd<95.1
where nd is the refractive index of the lens under d light, and vd is the dispersion coefficient of the lens under d light.
The focal positions of the visible light and the near infrared light are different due to the fact that the wavelengths of the visible light and the near infrared light are different, the focal positions of the visible light and the near infrared light are drawn to achieve the effect of confocal point through the lenses made of the materials with low refractive indexes and high dispersion ratios and the optical powers of the lenses are reasonably distributed, and day and night confocal is achieved. For example, the first lens L1 receives light into the lens, the negative power lens can reduce the size of the front end of the lens and further reduce the size of the rear end of the lens, the second lens L2 bends toward the object plane to correct distortion and adjust the angle of the light, the third lens L3 is a biconvex lens for correcting spherical aberration, chromatic aberration, etc. caused by the first lens L1 and the second lens L2, and the fourth lens L4 and the fifth lens L5 are lenses with negative light and positive power to further balance and correct the aberration.
By adopting at least one lens with low refractive index and high dispersion ratio and reasonably distributing the focal power of each lens, the focus drift amount of the lens in visible light and near infrared light wave bands is greatly reduced, day and night confocal is realized, the phenomenon of blue-purple edge in visible light is reduced, and the imaging definition and color authenticity are improved; the method can give consideration to clear imaging of 435-650 nm visible light and 830-870 nm near-infrared light, reasonably distributes positive and negative focal length values of each lens, solves the problem of optimized balance between high and low temperature focal drift and normal temperature resolving power, is free from virtual focus at high and low temperature, is suitable for temperature environment of-40-80 ℃, and has high imaging quality.
In one embodiment, the low index high dispersion lens is the first lens L1 or the third lens L3.
The first lens L1 and the third lens L3 are made of glass, and the second lens L2, the fourth lens L4 and the fifth lens L5 are made of plastic. Due to the 2G3P structure, the lens with low refractive index and high dispersion can be the first lens L1 or the third lens L3 or both. When the material of the lens is changed, the lens with low refractive index and high dispersion rate can also be other lenses made of glass. By adopting the 2G3P structure, the cost can be greatly reduced and the economic benefit can be improved when the large-scale production is carried out. And each lens can be selected to be a glass or plastic lens according to the use requirement.
In one embodiment, the day and night confocal security lens meets the following conditions:
0.17<f/TTL<0.32
wherein f is the focal length of the lens in mm, and TTL is the total optical length of the lens in mm.
In this embodiment, the total optical length TTL of the lens is less than or equal to 22 mm.
Under the condition that f/TTL is less than 0.17 and less than 0.32, if f is more than or equal to 3.8mm and less than or equal to 5.9mm and TTL is less than or equal to 22mm, further, f is 5.9mm, TTL is 22mm and f/TTL is 0.26, clear imaging is met, and meanwhile the lens size is reduced.
In one embodiment, the aspheric lens satisfies the following equation:
wherein Z is rise, c is reciprocal of curvature radius, y is radial coordinate, k is conic coefficient, A4、A6、A8、A10、A12、A14、A16、A18Are aspheric high order coefficients.
The aspheric lens can be used for correcting and focusing through a high-order curved surface, so that aberration is overcome, clear imaging is achieved, the structure is simplified, and the lens is miniaturized and light.
In one embodiment, the day and night confocal security lens further comprises a diaphragm, and the diaphragm is arranged between the first lens L1 and the second lens L2.
Wherein, the diaphragm setting is carried out light through adjusting the diaphragm and is adjusted between first lens L1 and second lens L2 for all can have fine quality of shooing day and night.
In one embodiment, the day and night confocal security lens further comprises an optical filter IRCUT and a protective glass, wherein the optical filter IRCUT is arranged between the fifth lens L5 and the image plane, and the optical filter IRCUT is close to the fifth lens L5.
The optical filter IRCUT is placed on one side, close to an image plane, of the fifth lens L5, and participates in light path imaging in daytime, near infrared light is filtered out, so that photoelectric noise is reduced, the near infrared light participates in imaging at night, the photosensitive brightness is enhanced, the imaging quality is improved, and the optical filter IRCUT is a conventional technology known by a person skilled in the art and is not repeated herein. The protective glass is located at the front end of the image plane and used for protecting the image plane from being scratched so as to avoid influencing imaging quality.
Further, the optical parameters of each mirror in this embodiment are as follows:
conic coefficient k and high-order aspheric coefficient A of each aspheric mirror surface in this embodiment4、A6、A8、A10、A12、A14、A16、A18The data are shown in the following table:
| L2R1 | L2R2 | L4R1 | L4R2 | L5R1 | L5R2 | |
| k | -17.5 | -5.47 | 15.66 | 0 | 8.49 | 17.18 |
| Α4 | -0.04 | 0.018 | -7.565e-3 | 2.1309e-3 | -3.46e-4 | 2.0409e-5 |
| Α6 | -0.014 | 2.127e-3 | -3.064e-4 | 2.705e-5 | -1.064 |
0 |
| Α8 | 0.0129 | -3.2e-3 | 5.2323e-4 | -5.069e-5 | 2.089 |
0 |
| Α10 | 0.0215 | -6.807e-3 | 1.267e-3 | -1.253e-4 | 4.95 |
0 |
| Α12 | 9.086e-3 | -3.77e-3 | 6.88e-4 | -5.911e-5 | 1.462 |
0 |
| Α14 | 1.67e-3 | -1.0e-4 | 3.84e-5 | -3.391e-6 | 1.173 |
0 |
| |
0 | 0 | 0 | 0 | 0 | 0 |
| |
0 | 0 | 0 | 0 | 0 | 0 |
the lens related parameters in the embodiment are as follows:
| f | F# | TTL | f/TTL |
| 5.9mm | 2.0 | 22mm | 0.26 |
based on the data in the table, the aperture can reach F #2.0, the total optical length TTL is controlled to be 22mm, and the spatial frequency is 80 lp/mm. As can be seen from fig. 2, the MTF of the full field under visible light is greater than 0.6, and the resolving power is higher, as can be seen from fig. 3, the MTF of the full field under near-infrared light is greater than 0.48, and the resolving power is also higher, so that the requirement of day and night confocal imaging is met, and a higher-definition imaging effect is achieved. FIG. 4 and FIG. 5 show the MTF conditions at-40 deg. and 80 deg., respectively, the MTF in the full field is greater than 0.6, the resolving power is equivalent to that at normal temperature, the focus drift amount is ensured to be within 0.01mm under the temperature condition of-40 deg. to 80 deg., and the purpose of optimally controlling the back focus drift amount at different temperatures is achieved. This application can compromise the clear formation of image of visible light and near-infrared light, realizes the confocal day night to positive negative focal length value through each lens of rational distribution, solve the optimization balance problem between high and low temperature focus drift and the normal atmospheric temperature analytic power, high and low temperature is not virtual burnt.
The above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same, and those skilled in the art can make various corresponding changes and modifications according to the present invention without departing from the spirit and the essence of the present invention, but these corresponding changes and modifications should fall within the protection scope of the appended claims of the present invention.
Claims (7)
1. The utility model provides a confocal security protection camera lens of day night which characterized in that: the day and night confocal security lens comprises a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5 which are sequentially arranged along the incident direction of light rays, wherein:
the first lens L1 is a negative-power convex-concave spherical lens;
the second lens L2 is a positive focal power concave-convex aspheric lens;
the third lens L3 is a positive focal power biconvex spherical lens;
the fourth lens L4 is a negative-focal power crescent aspheric lens;
the fifth lens L5 is a positive-power biconvex aspheric lens;
each lens comprises at least one lens with low refractive index and high dispersion rate, and the conditions are met:
1.437<nd<1.496，81.6<vd<95.1
where nd is the refractive index of the lens under d light, and vd is the dispersion coefficient of the lens under d light.
2. The day and night confocal security lens of claim 1, wherein: the low refractive index high dispersion lens is the first lens L1 or the third lens L3.
3. The day and night confocal security lens of claim 1, wherein: the day and night confocal security lens meets the following conditions:
0.17<f/TTL<0.32
wherein f is the focal length of the lens in mm, and TTL is the total optical length of the lens in mm.
4. The day and night confocal security lens of claim 3, wherein: the total optical length TTL of the lens is less than or equal to 22 mm.
5. The day and night confocal security lens of claim 1, wherein: the aspheric lens satisfies the following equation:
wherein Z is rise, c is reciprocal of curvature radius, y is radial coordinate, k is conic coefficient, A4、A6、A8、A10、A12、A14、A16、A18Are aspheric high order coefficients.
6. The day and night confocal security lens of claim 1, wherein: the day and night confocal security lens further comprises a diaphragm, and the diaphragm is arranged between the first lens L1 and the second lens L2.
7. The day and night confocal security lens of claim 6, wherein: the day and night confocal security lens further comprises an optical filter IRCUT and protective glass, wherein the optical filter IRCUT is arranged between the fifth lens L5 and an image plane, and the optical filter IRCUT is close to the fifth lens L5.
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| CN202021809774.6U CN212781469U (en) | 2020-08-26 | 2020-08-26 | Day and night confocal security lens |
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| CN202021809774.6U CN212781469U (en) | 2020-08-26 | 2020-08-26 | Day and night confocal security lens |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113933977A (en) * | 2021-11-05 | 2022-01-14 | 河南翊轩光电科技有限公司 | Confocal shimmer camera lens of 4k high definition day night |
| CN114397746A (en) * | 2022-01-22 | 2022-04-26 | 深圳融合光学科技有限公司 | Day and night dual-purpose prime lens and imaging method thereof |
-
2020
- 2020-08-26 CN CN202021809774.6U patent/CN212781469U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113933977A (en) * | 2021-11-05 | 2022-01-14 | 河南翊轩光电科技有限公司 | Confocal shimmer camera lens of 4k high definition day night |
| CN114397746A (en) * | 2022-01-22 | 2022-04-26 | 深圳融合光学科技有限公司 | Day and night dual-purpose prime lens and imaging method thereof |
| CN114397746B (en) * | 2022-01-22 | 2023-11-24 | 福建福光天瞳光学有限公司 | Day and night fixed focus lens and imaging method thereof |
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