CN217007834U - Short-focus monitoring lens - Google Patents
Short-focus monitoring lens Download PDFInfo
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- CN217007834U CN217007834U CN202220828665.1U CN202220828665U CN217007834U CN 217007834 U CN217007834 U CN 217007834U CN 202220828665 U CN202220828665 U CN 202220828665U CN 217007834 U CN217007834 U CN 217007834U
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Abstract
The utility model discloses a short-focus monitoring lens which comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object side to an image side along an optical axis, wherein the first lens has negative diopter, the second lens has negative diopter, the third lens has positive diopter, the fourth lens has negative diopter, the fifth lens has positive diopter, and the sixth lens has positive diopter, wherein the image side surface of the fourth lens is mutually glued with the object side surface of the fifth lens. The short-focus monitoring lens has the advantages of compact structure, short total length, small volume, lower cost and large light-passing aperture, and can still ensure the imaging effect in a dark environment.
Description
Technical Field
The utility model relates to the technical field of optical lenses, in particular to a short-focus monitoring lens.
Background
With the continuous progress of science and technology and the continuous development of society, optical imaging lenses have also been developed rapidly in recent years. The existing short-focus monitoring lens for indoor monitoring is generally longer in total length, large in outer diameter, large in lens volume, inconvenient to use and install, small in clear aperture, poor in imaging effect in a dark environment and higher in cost. In view of the above, the inventor of the present application invented a short focus monitoring lens.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a short-focus monitoring lens which is short in total length, small in size, low in cost and capable of ensuring an imaging effect in a low-illumination environment.
In order to realize the purpose, the utility model adopts the following technical scheme: a short-focus monitoring lens comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged 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 which faces the object side and enables imaging light rays to pass and an image side surface which faces the image side and enables the imaging light rays to pass;
the first lens has negative diopter, and the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;
the second lens has negative diopter, and the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface;
the third lens has positive diopter, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface;
the fourth lens has negative diopter, the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a concave surface;
the fifth lens has positive diopter, and the object-side surface of the fifth lens is a convex surface, and the image-side surface of the fifth lens is a convex surface;
the sixth lens has positive diopter, and the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface;
and the image side surface of the fourth lens and the object side surface of the fifth lens are mutually glued.
Further, the lens satisfies: 1.49< N1<1.89, 1.32< N2<1.72, 1.74< N3<2.14, 1.86< N4<2.26, 1.34< N5<1.74, 1.72< N6<2.12, wherein N1, N2, N3, N4, N5, N6 are refractive indexes of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens respectively.
Further, the lens satisfies: 54< V1<64, 67< V2<77, 16< V3<26, 13< V4<23, 62< V5<72, and 50< V6<60, wherein V1, V2, V3, V4, V5, and V6 are abbe coefficients of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens, respectively.
Further, the lens satisfies: TTL/f is less than 7.5, wherein TTL is the optical total length of the lens, and f is the focal length of the lens.
Further, the lens satisfies: dstop/f >0.6, wherein Dstop is the outer diameter of the diaphragm diameter, and f is the focal length of the lens.
Further, the lens satisfies: CD1/f >4, wherein CD1 is the effective clear aperture of the object side of the first lens, and f is the focal length of the lens.
Further, the first lens satisfies: w1<1g, wherein w1 is the weight of the first lens.
Further, the maximum light transmittance F/NO of the lens is 2.2.
After adopting the technical scheme, compared with the prior art, the utility model has the following advantages:
the short-focus monitoring lens has the advantages of compact structure, short total length, small volume, lower cost and large clear aperture, and can still ensure the imaging effect in a dark environment.
Drawings
FIG. 1 is a light path diagram of embodiment 1 of the present invention;
fig. 2 is a view illustrating curvature of field and distortion of a lens under visible light in embodiment 1 of the present invention;
fig. 3 is a graph of MTF under visible light of the lens in embodiment 1 of the present invention;
fig. 4 is a light ray fan diagram of the lens in visible light according to embodiment 1 of the present invention;
FIG. 5 is a light path diagram of embodiment 2 of the present invention;
fig. 6 is a field curvature and distortion diagram of a lens under visible light in embodiment 2 of the present invention;
fig. 7 is a graph of MTF under visible light of the lens in embodiment 2 of the present invention;
fig. 8 is a light ray fan diagram of a lens in visible light according to embodiment 2 of the present invention;
FIG. 9 is a light path diagram of embodiment 3 of the present invention;
fig. 10 is a field curvature and distortion diagram of a lens under visible light in embodiment 3 of the present invention;
fig. 11 is a graph of MTF under visible light for a lens in embodiment 3 of the present invention;
fig. 12 is a light fan diagram of a lens in visible light according to embodiment 3 of the present invention.
Description of reference numerals:
1. a first lens; 2. a second lens; 3. a third lens; 4. a fourth lens; 5. a fifth lens; 6. a sixth lens; 7. a diaphragm; 8. and (4) protecting the glass.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and do not limit the utility model.
As used herein, 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 Gaussian optics 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 can be commonly used in optical design software, such as Zemax or CodeV. The R value is also commonly found in lens data sheets (lens data 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 short-focus monitoring lens, in particular to a short-focus monitoring lens suitable for a small indoor space, which comprises a first lens 1, a second lens 2, a third lens 3, a diaphragm 7, a fourth lens 4, a fifth lens 5 and a sixth lens 6 which are sequentially arranged along an optical axis from an object side to an image side, wherein the first lens 1 to the sixth lens 6 respectively comprise an object side surface facing to the object side and enabling imaging light rays to pass and an image side surface facing to the image side and enabling the imaging light rays to pass;
the first lens 1 has negative diopter, and the object side surface of the first lens 1 is a convex surface, and the image side surface is a concave surface;
the second lens element 2 has negative diopter, and the object-side surface of the second lens element 2 is a convex surface and the image-side surface is a concave surface;
the third lens 3 has positive diopter, and the object side surface of the third lens 3 is a convex surface, and the image side surface is a convex surface;
the fourth lens 4 has negative diopter, and the object side surface of the fourth lens 4 is a concave surface, and the image side surface is a concave surface;
the fifth lens element 5 has positive refractive power, and the object-side surface of the fifth lens element 5 is a convex surface, and the image-side surface thereof is a convex surface;
the sixth lens element 6 has a positive refractive power, and the object-side surface of the sixth lens element 6 is a convex surface and the image-side surface is a convex surface.
The image side surface of the fourth lens 4 and the object side surface of the fifth lens 5 are mutually glued to form a cemented lens. The cemented lens is arranged between the diaphragm 7 and the sixth lens 6, so that the total length of the lens can be effectively shortened, and the miniaturization of the lens is realized; the negative diopter lens (the fourth lens 4) in the cemented lens is positioned on one side close to the diaphragm 7, and the positive diopter lens (the fifth lens 5) is positioned on one side close to the imaging surface, so that the off-axis light reaches the image surface in the shortest path, the total length of the system can be further reduced, and the miniaturization of the lens is realized.
The lens satisfies: 1.49< N1<1.89, 1.32< N2<1.72, 1.74< N3<2.14, 1.86< N4<2.26, 1.34< N5<1.74, 1.72< N6<2.12, wherein N1, N2, N3, N4, N5, and N6 are refractive indexes of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6, respectively.
The lens satisfies: 54< V1<64, 67< V2<77, 16< V3<26, 13< V4<23, 62< V5<72, and 50< V6<60, wherein V1, V2, V3, V4, V5, and V6 are abbe coefficients of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6, respectively.
The lens satisfies: TTL/f is less than 7.5, wherein TTL is the optical total length of the lens, and f is the focal length of the lens. The design is beneficial to miniaturization of the lens.
The lens satisfies: dstop/f >0.6, where Dstop is the outer diameter of the diaphragm 7 diameter and f is the focal length of the lens. The design can reduce the F value of the system, so that the lens can still clearly image in a low-illumination environment, and the low-illumination effect of the lens is good.
The lens satisfies: CD1/f >4, wherein CD1 is the effective clear aperture of the object side of the first lens 1, and f is the focal length of the lens. The design ensures that more light rays enter the system, the light ray dispersion range is large, and the sensitivity of the lens is low.
The first lens 1 satisfies: w1<1g, wherein w1 is the weight of the first lens 1. The lower the weight, the lower the cost of the lens, with a constant density, and this weight design results in a lower cost lens.
The lens has a large light-passing aperture, the maximum light-passing F/NO is 2.2, and the imaging effect in a dark environment is good.
The short focus monitoring lens of the present invention will be described in detail with specific embodiments.
Example 1
Referring to fig. 1, the present invention discloses a short focus monitoring lens, including a first lens 1, a second lens 2, a third lens 3, a diaphragm 7, a fourth lens 4, a fifth lens 5, and a sixth lens 6, which are sequentially disposed along an optical axis from an object side to an image side, where the first lens 1 to the sixth lens 6 each include an object side surface facing the object side and allowing an imaging light to pass therethrough, and an image side surface facing the image side and allowing the imaging light to pass therethrough;
the first lens 1 has negative diopter, and the object side surface of the first lens 1 is a convex surface, and the image side surface is a concave surface;
the second lens element 2 has negative diopter, and the object-side surface of the second lens element 2 is a convex surface and the image-side surface is a concave surface;
the third lens element 3 has a positive refractive power, and an object-side surface of the third lens element 3 is a convex surface and an image-side surface thereof is a convex surface;
the fourth lens 4 has negative diopter, and the object side surface of the fourth lens 4 is a concave surface, and the image side surface is a concave surface;
the fifth lens 5 has positive diopter, and the object side surface of the fifth lens 5 is a convex surface, and the image side surface is a convex surface;
the sixth lens element 6 has a positive refractive power, and the object-side surface of the sixth lens element 6 is a convex surface and the image-side surface is a convex surface.
The image side surface of the fourth lens 4 and the object side surface of the fifth lens 5 are mutually glued.
The detailed optical data of this embodiment are shown in Table 1-1.
Table 1-1 detailed optical data for example 1
In this example, TTL/f is 6.7, Dstop/f is 0.8, CD1/f is 4.9, and w1 is 0.7 g.
Please refer to fig. 2 for the field curvature and distortion diagram of the lens under visible light, it can be seen from the diagram that the field curvature of the lens is less than 0.2mm, and the optical distortion of the system is < -100% |, which satisfies the use requirement.
In this embodiment, please refer to fig. 3 for an MTF graph of the lens under visible light, and it can be seen from the graph that when the spatial frequency of the lens reaches 125lp/mm, the MTF value is greater than 0.3, the imaging quality is good, the resolution of the lens is good, and the use requirement is met.
See fig. 4 for a ray fan diagram of the lens under visible light, wherein the abscissa is the normalized field of view from-1 to 1, in tenths, each cell is 0.2, and the unit is dimensionless. The ordinate is the aberration value, the maximum ratio is plus or minus 20um, in microns. The left graph is in the meridian direction, the right graph is in the sagittal direction, the aberrations of the wavelengths from 486 to 656 of the linear scanning lens are highly coincident, the 650nm wavelength aberration is the largest in visible light, the maximum value is about 4um, the curve is parabolic, and the variation trends of the aperture field ranges of all wavelengths are the same and similar.
Example 2
As shown in fig. 5, the present embodiment is different from embodiment 1 mainly in the optical parameters such as the curvature radius of each lens surface and the lens thickness.
The detailed optical data of this embodiment is shown in Table 2-1.
Table 2-1 detailed optical data for example 2
In this example, TTL/f is 6.8, Dstop/f is 0.81, CD1/f is 5.2, and w1 is 0.8 g.
Please refer to fig. 6 for the field curvature and distortion diagram of the lens under visible light, it can be seen from the diagram that the field curvature of the lens is less than 0.2mm, and the optical distortion of the system is < -100% |, which satisfies the use requirement.
In this embodiment, please refer to fig. 7 for an MTF graph of the lens under visible light, and it can be seen from the graph that when the spatial frequency of the lens reaches 125lp/mm, the MTF value is greater than 0.3, the imaging quality is good, the resolution of the lens is good, and the use requirement is met.
See fig. 8 for a ray fan diagram of the lens under visible light, wherein the abscissa is the normalized field of view from-1 to 1, in tenths, each cell is 0.2, and the unit is dimensionless. The ordinate is the aberration value, the maximum ratio is plus or minus 20um, in microns. The left graph is in the meridian direction, the right graph is in the sagittal direction, the aberrations of the wavelengths from 486 to 656 of the linear scanning lens are highly coincident, the 650nm wavelength aberration is the largest in visible light, the maximum value is about 4um, the curve is parabolic, and the variation trends of the aperture field ranges of all wavelengths are the same and similar.
Example 3
As shown in fig. 9, this embodiment is different from embodiment 1 mainly in the optical parameters such as the curvature radius of each lens surface and the lens thickness.
The detailed optical data of this embodiment is shown in Table 3-1.
Table 3-1 detailed optical data for example 3
In this example, TTL/f is 6.8, Dstop/f is 0.83, CD1/f is 5.1, and w1 is 0.81 g.
Please refer to fig. 10 for the field curvature and distortion diagram of the lens under visible light, it can be seen from the diagram that the field curvature of the lens is less than 0.2mm, and the optical distortion of the system is < -100% |, which satisfies the use requirement.
In this embodiment, please refer to fig. 11 for an MTF graph of the lens under visible light, and it can be seen from the graph that when the spatial frequency of the lens reaches 125lp/mm, the MTF value is greater than 0.3, the imaging quality is good, the resolution of the lens is good, and the use requirement is met.
See fig. 12 for a ray fan diagram of a lens under visible light, wherein the abscissa is the normalized field of view from-1 to 1, in tenths, each cell is 0.2, and the unit is dimensionless. The ordinate is the aberration value, the maximum ratio is plus or minus 20um, in microns. The left graph is in the meridian direction, the right graph is in the sagittal direction, the aberrations of the wavelengths from 486 to 656 of the linear scanning lens are highly coincident, the 650nm wavelength aberration is the largest in visible light, the maximum value is about 4um, the curve is parabolic, and the variation trends of the aperture field ranges of all wavelengths are the same and similar.
While the utility model has been described with reference to specific preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the utility model as defined in the following claims. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A short focus monitoring lens is characterized in that: the imaging lens comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged along an optical axis from an object side to an image side, 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 has negative diopter, and the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;
the second lens has negative diopter, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface;
the third lens has positive diopter, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface;
the fourth lens has negative diopter, the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a concave surface;
the fifth lens has positive diopter, and the object-side surface of the fifth lens is a convex surface, and the image-side surface of the fifth lens is a convex surface;
the sixth lens element has positive refractive power, and has a convex object-side surface and a convex image-side surface;
and the image side surface of the fourth lens and the object side surface of the fifth lens are mutually glued.
2. The short focus monitoring lens of claim 1, wherein: the lens satisfies: 1.49< N1<1.89, 1.32< N2<1.72, 1.74< N3<2.14, 1.86< N4<2.26, 1.34< N5<1.74, and 1.72< N6<2.12, wherein N1, N2, N3, N4, N5, and N6 are refractive indexes of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens, respectively.
3. The short focus monitoring lens of claim 1, wherein: the lens satisfies: 54< V1<64, 67< V2<77, 16< V3<26, 13< V4<23, 62< V5<72, and 50< V6<60, wherein V1, V2, V3, V4, V5, and V6 are abbe coefficients of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens, respectively.
4. The short focus monitoring lens of claim 1, wherein: the lens satisfies the following conditions: TTL/f is less than 7.5, wherein TTL is the optical total length of the lens, and f is the focal length of the lens.
5. The short focus monitoring lens of claim 1, wherein: the lens satisfies: dstop/f >0.6, wherein Dstop is the outer diameter of the diaphragm diameter, and f is the focal length of the lens.
6. The short focus monitoring lens of claim 1, wherein: the lens satisfies the following conditions: CD1/f >4, wherein CD1 is the effective clear aperture of the object side of the first lens, and f is the focal length of the lens.
7. The short focus monitoring lens of claim 1, wherein: the first lens satisfies: w1<1g, wherein w1 is the weight of the first lens.
8. The short focus monitoring lens of claim 1, wherein: the maximum light transmission F/NO of the lens is 2.2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220828665.1U CN217007834U (en) | 2022-04-11 | 2022-04-11 | Short-focus monitoring lens |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220828665.1U CN217007834U (en) | 2022-04-11 | 2022-04-11 | Short-focus monitoring lens |
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| Publication Number | Publication Date |
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| CN217007834U true CN217007834U (en) | 2022-07-19 |
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| CN202220828665.1U Active CN217007834U (en) | 2022-04-11 | 2022-04-11 | Short-focus monitoring lens |
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- 2022-04-11 CN CN202220828665.1U patent/CN217007834U/en active Active
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