CN117647873A - Fixed focus lens and monitoring equipment - Google Patents
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- CN117647873A CN117647873A CN202311852291.2A CN202311852291A CN117647873A CN 117647873 A CN117647873 A CN 117647873A CN 202311852291 A CN202311852291 A CN 202311852291A CN 117647873 A CN117647873 A CN 117647873A
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- 238000012544 monitoring process Methods 0.000 title abstract description 15
- 230000003287 optical effect Effects 0.000 claims abstract description 29
- 238000003384 imaging method Methods 0.000 claims description 22
- 239000011521 glass Substances 0.000 claims description 18
- 239000006185 dispersion Substances 0.000 claims description 8
- 229920003023 plastic Polymers 0.000 claims description 8
- 239000004033 plastic Substances 0.000 claims description 8
- 238000012806 monitoring device Methods 0.000 claims description 3
- 239000006059 cover glass Substances 0.000 claims 2
- 238000005286 illumination Methods 0.000 abstract description 7
- 230000007613 environmental effect Effects 0.000 abstract description 4
- 230000004075 alteration Effects 0.000 description 16
- 238000010586 diagram Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 230000001681 protective effect Effects 0.000 description 5
- 201000009310 astigmatism Diseases 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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Abstract
The invention discloses a fixed-focus lens and monitoring equipment, wherein the fixed-focus lens is provided with an object side and an image side which are oppositely arranged along the optical axis direction, the fixed-focus lens comprises a first lens with negative focal power, a second lens with positive focal power, a diaphragm, a third lens with positive focal power, a fourth lens with negative focal power and a fifth lens with positive focal power, which are sequentially arranged from the object side to the image side, and the fixed-focus lens meets the following conditions: 1.1 < |f1/f| < 2.2, 5< |f2/f| < 10,1.6 < |f3/f| < 3, 1 < |f4/f| < 1.9, and 1 < |f5/f| < 1.8, wherein the aperture value F of the fixed focus lens satisfies 1.5.ltoreq.F.ltoreq.2.1, the fixed focus lens can clearly image under low illumination, and the lens is not defocused under the environmental condition of minus 40 ℃ to +80 ℃ by reasonably setting the focal length ratio, the working performance is more stable, the field angle can reach 130 degrees, and the field of view is wider, so as to provide a high-definition fixed focus lens with large aperture, large field angle and good temperature stability.
Description
Technical Field
The invention relates to the technical field of optics, in particular to a fixed focus lens and monitoring equipment.
Background
In recent years, security monitoring systems are becoming more common in daily life, wherein a fixed focus lens is an indispensable part of the security monitoring system, and the cost requirement for monitoring the fixed focus lens is also becoming higher. The current fixed focus lens generally uses more glass lenses, thereby causing cost rise and weight increase. Meanwhile, the requirements on shooting under the condition of dark light are higher and higher, the aperture of the current monitoring lens is generally about 2.0, the aperture is smaller, imaging is not ideal under low illumination such as early morning, evening and the like, an imaging picture is dark, and picture noise is more; and all adopt glass lens, the lens cost is big, weight is great, and the angle of view is also less.
Disclosure of Invention
The invention mainly aims to provide a fixed-focus lens and monitoring equipment, and aims to provide a high-definition fixed-focus lens with large aperture, large field angle and good temperature stability.
In order to achieve the above object, the present invention provides a fixed focus lens, which has an object side and an image side that are disposed opposite to each other along an optical axis direction, the fixed focus lens includes a first lens with negative focal power, a second lens with positive focal power, a diaphragm, a third lens with positive focal power, a fourth lens with negative focal power, and a fifth lens with positive focal power, which are disposed in order from the object side to the image side, and the fixed focus lens satisfies the following conditions:
1.1 < |f1/f| < 2.2, and 5< |f2/f| < 10,1.6 < |f3/f| < 3, and 1 < |f4/f| < 1.9, and 1 < |f5/f| < 1.8.
Wherein f is the total focal length of the fixed focus lens, 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, and f5 is the focal length of the fifth lens.
Optionally, the first lens, the second lens, the fourth lens and the fifth lens are plastic lenses;
the third lens is a glass lens.
Optionally, the first lens, the second lens, the fourth lens and the fifth lens are aspheric lenses;
the third lens is a spherical lens.
Optionally, the diaphragm and the fixed focus lens meet the following conditions: SD/TTL is more than 0.4 and less than 0.8;
wherein SD is the distance between the aperture and the imaging surface of the fixed focus lens on the optical axis, and TTL is the total optical length of the fixed focus lens.
Optionally, the total optical length 17 of the fixed focus lens is less than TTL less than 30.
Optionally, the fixed focus lens further satisfies the following condition: 5< TTL/f <9.3;
wherein f is the focal length of the fixed focus lens, and TTL is the total optical length of the fixed focus lens.
Optionally, the fourth lens has an abbe number vd4 that satisfies: vd4 is more than 20 and less than 40;
the dispersion coefficient vd5 of the fifth lens satisfies: 40 < vd 5< 70.
Optionally, the object side surface of the first lens is a convex surface or a concave surface, and the image side surface of the first lens is a concave surface;
the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface;
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 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 object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface.
Optionally, the fixed focus lens further includes a protective glass and a photosensitive chip sequentially from the object side to the image side, where the protective glass and the photosensitive chip are disposed on a side of the fifth lens close to the image side.
The invention also provides monitoring equipment which comprises the fixed focus lens.
According to the technical scheme provided by the invention, a first lens with negative focal power, a second lens with positive focal power, a third lens with positive focal power, a fourth lens with negative focal power and a fifth lens with positive focal power are sequentially arranged from an object side to an image side, more optical information can be collected under the condition of the same focal length through a large caliber of the first lens, the effect of clear imaging under low illumination is achieved, meanwhile, axial chromatic aberration is corrected, the volume of a lens is reduced, off-axis astigmatism is corrected through the second lens, the diaphragm is used for adjusting luminous flux according to actual conditions, the imaging quality can be improved, the third lens can correct chromatic aberration of a system and curvature of an image surface, the aperture of the system is increased, the imaging performance of the optical system under high and low temperatures is ensured, the fourth lens and the fifth lens can correct chromatic aberration of the system and spherical aberration of the image surface curvature, and the fixed focal lens meets the following conditions: 1.1 < |f1/f| < 2.2, 5< |f2/f| < 10,1.6 < |f3/f| < 3, 1 < |f4/f| < 1.9, and 1 < |f5/f| < 1.8, the fixed focus lens can well control light trend through reasonable arrangement of optical power and shape of five lenses, more light is introduced, the structure is more compact, the aperture value F of the fixed focus lens meets 1.5-F < 2.1, the fixed focus lens can clearly image under low illumination, the lens is not defocused under the environmental condition of minus 40-80 ℃ through reasonable setting of focal length ratio, the working performance is more stable, the angle of view can reach 130 degrees, the field of view is wider, and more sufficient data information is obtained, so that the fixed focus lens with large aperture, large angle of view and high temperature stability is provided.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a fixed focus lens provided by the invention;
FIG. 2 is a schematic diagram of a spherical aberration curve of the fixed focus lens of FIG. 1;
FIG. 3 is a schematic view of a light fan of the fixed focus lens of FIG. 1;
fig. 4 is a distortion/curvature of field diagram of the fixed focus lens of fig. 1.
Reference numerals illustrate:
| reference numerals | Name of the name | Reference numerals | Name of the name |
| 1 | First lens | 5 | Fifth lens |
| 2 | Second lens | 6 | Diaphragm |
| 3 | Third lens | 7 | Protective glass |
| 4 | Fourth lens | 8 | Photosensitive chip |
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present invention, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
In recent years, security monitoring systems are becoming more common in daily life, wherein a fixed focus lens is an indispensable part of the security monitoring system, and the cost requirement for monitoring the fixed focus lens is also becoming higher. The current fixed focus lens generally uses more glass lenses, thereby causing cost rise and weight increase. Meanwhile, the requirements on shooting under the condition of dark light are higher and higher, the aperture of the current monitoring lens is generally about 2.0, the aperture is smaller, imaging is not ideal under low illumination such as early morning, evening and the like, an imaging picture is dark, and picture noise is more; and all adopt glass lens, the lens cost is big, weight is great, and the angle of view is also less.
In order to solve the above-mentioned problems, the present invention provides a fixed-focus lens, and fig. 1 to fig. 4 are specific embodiments of the fixed-focus lens provided by the present invention.
Referring to fig. 1, the fixed focus lens has an object side and an image side disposed opposite to each other along an optical axis, the fixed focus lens includes a first lens 1 with negative focal power, a second lens 2 with positive focal power, a diaphragm 6, a third lens 3 with positive focal power, a fourth lens 4 with negative focal power, and a fifth lens 5 with positive focal power, which are disposed in order from the object side to the image side, and the fixed focus lens satisfies the following conditions: 1.1 < |f1/f| < 2.2, and 5< |f2/f| < 10,1.6 < |f3/f| < 3, and 1 < |f4/f| < 1.9, and 1 < |f5/f| < 1.8. Wherein f is the total focal length of the fixed focus lens, f1 is the focal length of the first lens 1, f2 is the focal length of the second lens 2, f3 is the focal length of the third lens 3, f4 is the focal length of the fourth lens 4, and f5 is the focal length of the fifth lens 5.
According to the technical scheme provided by the invention, a first lens 1 with negative focal power, a second lens 2 with positive focal power, a third lens 3 with positive focal power, a fourth lens 4 with negative focal power and a fifth lens 5 with positive focal power are sequentially arranged from an object side to an image side, more light information can be collected under the condition of the same focal length through a large caliber of the first lens 1, the effect of clear imaging under low illumination is achieved, meanwhile, axial chromatic aberration is corrected, the volume of a lens is reduced, the astigmatism outside the axis is corrected through the second lens 2, the diaphragm 6 is used for adjusting the luminous flux according to actual conditions, the imaging quality can be improved, the third lens 3 can correct the chromatic aberration and the image surface curvature of a system, the aperture of the system is increased, the imaging performance of the optical system under high and low temperatures is ensured, the fourth lens 4 and the fifth lens 5 can correct the chromatic aberration and the spherical aberration of the system and the image surface curvature, and the fixed focal lens meets the following conditions: 1.1 < |f1/f| < 2.2, 5< |f2/f| < 10,1.6 < |f3/f| < 3, 1 < |f4/f| < 1.9, and 1 < |f5/f| < 1.8, the fixed focus lens can well control light trend through reasonable arrangement of optical power and shape of five lenses, more light is introduced, the structure is more compact, the aperture value F of the fixed focus lens meets 1.5-F < 2.1, the fixed focus lens can clearly image under low illumination, the lens is not defocused under the environmental condition of minus 40-80 ℃ through reasonable setting of focal length ratio, the working performance is more stable, the angle of view can reach 130 degrees, the field of view is wider, and more sufficient data information is obtained, so that the fixed focus lens with large aperture, large angle of view and high temperature stability is provided.
It is understood that |f1/f| can be: 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, etc., the/f 2/f may be: 5.1, 5.6, 6.1, 6.6, 7.1, 7.6, 8.1, 8.6, 9.1, etc., may be 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, etc., may be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, etc., and may be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, etc., and may be 1.1, 1.5, 1.6, 1.7, etc.
Specifically, since the impact resistance of the resin lens is strong, the weight is light, and the cost is low, in this embodiment, the materials of the first lens 1, the second lens 2, the fourth lens 4, and the fifth lens 5 are plastics, and the cost is effectively controlled by adopting the plastic aspherical lens. However, since the plastic material is unstable due to the chemical characteristics of the plastic material affected by the ambient temperature, the refractive index of the plastic material is weaker than that of the all-glass lens, so that the image reduction degree is inferior to that of the all-glass lens, and in order to ensure the stability of the video lens due to the temperature change, in this embodiment, the third lens 3 is a glass spherical lens. Because the glass lens is not easy to be influenced by expansion caused by heat and contraction caused by cold, the glass lens can well resist the problem of deformation of the lens caused by heat, and the high precision of the lens is maintained for a long time. The aberration generated during imaging can be eliminated as much as possible, so that the imaging quality of the lens is improved, and the influence of temperature on the optical performance of the lens can be reduced.
The fixed focus lens is made of glass-plastic mixed materials, so that the cost is saved, the shock resistance is high, and the stability of the system and the applicability of high and low temperatures are ensured.
Specifically, in the present embodiment, the diaphragm 6 and the fixed focus lens satisfy the following conditions: SD/TTL is more than 0.4 and less than 0.8; wherein SD is the distance between the diaphragm 6 and the imaging surface of the fixed focus lens on the optical axis, and TTL is the total optical length of the fixed focus lens. The total optical system length (TTL) generally refers to the length of the entire optical system, i.e., the distance from the front surface of the first lens (or objective lens) to the image plane, and can be understood as the size and structure of the entire optical system of the fixed focus lens. The focal length (f) is the distance from the rear surface of the objective lens to the image plane in the optical system, and determines the magnification and viewing angle of the image.
Specifically, in this embodiment, the total optical length 17 < TTL < 30 of the fixed focus lens. Therefore, more light rays are introduced, and meanwhile, the fixed focus lens is compact in structure and small in size, and meets the miniaturization characteristic of monitoring equipment.
Specifically, the fixed focus lens also satisfies the following conditions: 5< TTL/f <9.3; wherein f is the focal length of the fixed focus lens, and TTL is the total optical length of the fixed focus lens.
Specifically, in the present embodiment, the dispersion coefficient vd4 of the fourth lens 4 satisfies: 20 < vd4 < 40.
Specifically, in the present embodiment, the dispersion coefficient vd5 of the fifth lens 5 satisfies: 40 < vd 5< 70. The larger the dispersion coefficient (abbe number), the less obvious the dispersion, the better the imaging quality of the lens, and each lens in the embodiment controls the dispersion coefficient to be a higher value, so that the dispersion of the fixed focus lens is less obvious, and the imaging quality of the lens is good.
Specifically, the object side surface of the first lens element 1 is a convex surface or a concave surface, and the image side surface of the first lens element 1 is a concave surface; the object side surface of the second lens element 2 is concave, and the image side surface of the second lens element 2 is convex; the object side surface of the third lens element 3 is convex, and the image side surface of the third lens element 3 is convex; the object side surface of the fourth lens element 4 is a concave surface, and the image side surface of the fourth lens element 4 is a concave surface; the object side surface of the fifth lens element 5 is convex, and the image side surface of the fifth lens element 5 is convex.
Further, in this embodiment, the fixed focus lens further includes a protective glass 7 and a photosensitive chip 8 in order from the object side to the image side, where the protective glass 7 and the photosensitive chip 8 are disposed on a side of the fifth lens 5 near the image side. The protection glass 7 can provide effective protection for the photosensitive chip 8IMAGE, the protection glass 7 can be arranged as an optical filter, and the optical filter can effectively filter stray light of a non-working wave band so as to reduce optical noise and reduce difficulty for a subsequent photoelectric module processing part, thereby improving imaging quality. It will be appreciated that the surface of the photosensitive chip 8 facing the object side is an imaging surface.
Specifically, the imaging surface may be understood as a surface of the photosensitive chip 8 facing the object side, that is, a surface of an imaging element such as a CCD or a CMOS, and it may be understood that light carrying subject information may sequentially pass through the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 5 and finally be imaged on the imaging surface.
Specifically, in this embodiment, the refractive index, the radius of curvature and the thickness interval of the lens material are shown in table 1 below:
TABLE 1
Specifically, in the present embodiment, the first lens 1, the second lens 2, the fourth lens 4, and the fifth lens 5 are aspherical lenses. The aspherical lens is characterized in that: the curvature continuously varies from the lens center to the lens periphery, and unlike a spherical lens having a constant curvature from the lens center to the lens periphery, an aspherical lens has a better radius of curvature characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. And the chromatic aberration of the lens can be well corrected through the aspheric lens, and under the condition of guaranteeing the control of the purple side of the lens, the spherical aberration and the sine difference at the high-power position are corrected at the same time.
Further, in the present embodiment, the aspherical surface shape of the aspherical lens satisfies the following condition:
wherein c is the curvature corresponding to the radius, y is the radial coordinate (the unit is the same as the unit of the lens length), k is the conic coefficient, (the surface shape curve is hyperbolic when the k coefficient is smaller than-1, parabola when the k coefficient is equal to-1, ellipse when the k coefficient is between-1 and 0, circle when the k coefficient is equal to 0, oblate when the k coefficient is larger than 0), a1, a2, a3, a4, a5, a6, a7 are the higher aspheric coefficients (please refer to the following table 2), and the shape and size of the aspheric surfaces of the object side and the image side of the lens can be set through the parameters.
Table 2 conical coefficients and aspherical coefficients for aspherical lenses:
| sequence number | K | a1 | a2 | a3 | a4 | a5 | a6 | a7 |
| S1 | -44.37 | -2.21E-04 | -8.26E-06 | 3.18E-07 | -2.10E-09 | 0.00E+00 | 0.00E+00 | 0.00E+00 |
| S2 | -1.05 | 6.20E-03 | -2.77E-06 | 1.34E-04 | -3.21E-05 | 4.56E-06 | -2.75E-07 | 4.80E-10 |
| S3 | 5.94 | 1.11E-03 | -1.71E-04 | 8.41E-05 | -1.32E-05 | 3.16E-07 | 7.81E-08 | -2.14E-09 |
| S4 | -0.10 | 1.07E-04 | -8.93E-05 | 1.92E-05 | -2.14E-06 | -2.65E-07 | 8.01E-08 | -5.00E-09 |
| S8 | 53.98 | -9.42E-03 | 1.02E-03 | -1.40E-04 | 4.69E-06 | 5.98E-07 | 2.75E-08 | -8.57E-09 |
| S9 | -0.85 | -1.10E-02 | 8.84E-04 | -1.22E-04 | 1.07E-05 | 2.06E-07 | -1.32E-07 | 6.39E-09 |
| S10 | -0.55 | -4.87E-03 | -5.28E-04 | 8.27E-05 | -1.18E-06 | -4.32E-07 | 1.86E-08 | 1.07E-09 |
| S11 | -4.91 | -3.88E-03 | 4.17E-05 | 2.70E-05 | -2.46E-06 | 2.23E-08 | 1.95E-08 | 1.21E-09 |
Fig. 2 is a schematic diagram of a spherical aberration curve of an embodiment of a fixed focus lens according to the present invention, fig. 3 is a schematic diagram of a light fan of an embodiment of a fixed focus lens according to the present invention, and fig. 4 is a schematic diagram of field distortion/field curvature of an embodiment of a fixed focus lens according to the present invention.
As can be seen from the above figures, the spherical aberration, curvature of field, and distortion of the fixed focus lens in the present embodiment can be well corrected.
In summary, the aperture value F of the fixed-focus lens meets the requirement that F is more than or equal to 1.5 and less than or equal to 2.1, and the fixed-focus lens is not out of focus under the environmental condition of minus 40 ℃ to plus 80 ℃, and the field angle can reach 130 degrees.
The invention also provides a monitoring device, which comprises the fixed-focus lens according to the technical scheme, wherein the specific structure of the fixed-focus lens refers to the embodiment, and the fixed-focus lens of the fixed-focus lens adopts all the technical schemes of all the embodiments, so that the monitoring device at least has all the beneficial effects brought by the technical schemes of the embodiments, and the specific structure of the fixed-focus lens is not repeated herein.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (10)
1. The utility model provides a fixed focus camera lens, its characterized in that, fixed focus camera lens has and is relative object side and the image side that sets up along the optical axis direction, fixed focus camera lens includes that the focal power that sets gradually is negative first lens, focal power is positive second lens, diaphragm, focal power be positive third lens, focal power be negative fourth lens, focal power be positive fifth lens from the object side to the image side, fixed focus camera lens satisfies the following condition:
1.1 < |f1/f| < 2.2, and 5< |f2/f| < 10,1.6 < |f3/f| < 3, and 1 < |f4/f| < 1.9, and 1 < |f5/f| < 1.8.
Wherein f is the total focal length of the fixed focus lens, 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, and f5 is the focal length of the fifth lens.
2. The fixed focus lens of claim 1 wherein the first lens, the second lens, the fourth lens, and the fifth lens are plastic lenses;
the third lens is a glass lens.
3. The fixed focus lens of claim 1, wherein the first lens, the second lens, the fourth lens, and the fifth lens are aspherical lenses;
the third lens is a spherical lens.
4. The fixed focus lens of claim 1, wherein the diaphragm and the fixed focus lens satisfy the following conditions: SD/TTL is more than 0.4 and less than 0.8;
wherein SD is the distance between the aperture and the imaging surface of the fixed focus lens on the optical axis, and TTL is the total optical length of the fixed focus lens.
5. The fixed focus lens of claim 1 wherein the fixed focus lens has an optical total length 17 < TTL < 30.
6. The fixed focus lens of claim 1, wherein the fixed focus lens further satisfies the following condition: 5< TTL/f <9.3;
wherein f is the focal length of the fixed focus lens, and TTL is the total optical length of the fixed focus lens.
7. The fixed focus lens of claim 1 wherein the fourth lens has an abbe number vd4 that satisfies: vd4 is more than 20 and less than 40;
the dispersion coefficient vd5 of the fifth lens satisfies: 40 < vd 5< 70.
8. The fixed focus lens of claim 1, wherein an object side surface of the first lens is a convex surface or a concave surface, and an image side surface of the first lens is a concave surface;
the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface;
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 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 object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface.
9. The fixed focus lens of claim 1, further comprising a cover glass and a photosensitive chip in order from an object side to an image side, wherein the cover glass and the photosensitive chip are disposed on a side of the fifth lens close to the image side.
10. A monitoring device, characterized by a fixed focus lens as claimed in any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311852291.2A CN117647873A (en) | 2023-12-28 | 2023-12-28 | Fixed focus lens and monitoring equipment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311852291.2A CN117647873A (en) | 2023-12-28 | 2023-12-28 | Fixed focus lens and monitoring equipment |
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| Publication Number | Publication Date |
|---|---|
| CN117647873A true CN117647873A (en) | 2024-03-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311852291.2A Pending CN117647873A (en) | 2023-12-28 | 2023-12-28 | Fixed focus lens and monitoring equipment |
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| Country | Link |
|---|---|
| CN (1) | CN117647873A (en) |
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2023
- 2023-12-28 CN CN202311852291.2A patent/CN117647873A/en active Pending
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