Day and night confocal lenses and imaging devices

Abstract

The present invention discloses a day-night confocal lens and an imaging device. The day-night confocal lens includes a first convex-concave lens with a negative optical power, a second biconcave lens with a negative optical power, a third convex-concave lens with a negative optical power, a fourth biconvex lens with a positive optical power, a fifth biconcave lens with a negative optical power, and a sixth biconvex lens with a positive optical power. By rationally setting the optical powers and shapes of the six lenses, the day-night confocal lens can well control the direction of light, while introducing more light and making the structure more compact. The total length of the day-night confocal lens is controlled within 13 mm, and the aperture value F satisfies 1.8≤F≤2.4, supporting a 1 / 2.7-inch image plane. The day-night confocal lens can also clearly image in low light. By rationally setting the focal length ratio, the lens does not defocus under environmental conditions of -40°C to +85°C, the operating performance is more stable, and the field of view angle can reach 195°±5%, thereby providing a small day-night confocal lens with an ultra-large field of view and day-night confocal capability.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, in particular to a day and night confocal lens and an imaging device. Background Art

[0002] With the rapid development of technology, wide-angle lenses, due to their advantages of large field of view and wide image format, are widely used in security, automotive, smart home and other fields. However, due to the differences in application environments, consumer requirements are also becoming increasingly demanding. In some complex application scenarios, the lens must be able to maintain focus under conditions of large temperature swings between high and low temperatures, while also ensuring effective operation in both daytime and night conditions to meet shooting needs. The current consumer market trend is towards low cost and miniaturization, but many similar products have multiple lenses and complex structures. Therefore, the research on miniaturized and low-cost day and night confocal lenses is highly practical. Summary of the Invention

[0003] The main purpose of the present invention is to propose a day and night confocal lens and an imaging device, aiming to provide a small day and night confocal lens with an ultra-large field of view and capable of day and night confocality.

[0004] To achieve the above objectives, the present invention provides a day-night confocal lens having an object side and an image side disposed opposite each other along an optical axis. The day-night confocal lens includes, arranged in order from the object side to the image side, a first convex-concave lens with negative optical power, a second biconcave lens with negative optical power, a third convex-concave lens with negative optical power, a fourth biconcave lens with positive optical power, a fifth biconcave lens with negative optical power, and a sixth biconvex lens with positive optical power, wherein the concave surfaces of the first convex-concave lens and the third convex-concave lens are disposed toward the image side.

[0005] The total optical length TTL of the day and night confocal lens is ≤13 mm, the aperture number of the day and night confocal lens is F, and 1.8≤F≤2.4, and the field of view FOV=195°±5%.

[0006] Optionally, the day and night confocal lens further meets the following conditions:

[0007] -4<f1<-2; -5.4<f2<-4.6; 2.6<f3<4.8; 2.4<f4<4.0; -3.2<f5<-1.6; 2.4<f6<3.5;

[0008] Among them, the focal length of the first convex-concave lens is f1, the focal length of the second biconcave lens is f2, the focal length of the third convex-concave lens is f3, the focal length of the fourth biconvex lens is f4, the focal length of the fifth biconcave lens is f5, and the focal length of the sixth biconvex lens is f6.

[0009] Optionally, the day and night confocal lens further meets the following conditions:

[0010] 1.60≤n1≤1.80;1.50≤n2≤1.60;1.55≤n3≤1.70;1.50≤n4≤1.70;1.60≤n5≤1.70;1.50≤n6≤1.75;

[0011] Among them, the refractive index of the first convex-concave lens is n1, the refractive index of the second biconcave lens is n2, the refractive index of the third convex-concave lens is n3, the refractive index of the fourth biconvex lens is n4, the refractive index of the fifth biconcave lens is n5, and the refractive index of the sixth biconvex lens is n6.

[0012] Optionally, the day and night confocal lens further meets the following conditions:

[0013] 50.0≤v1≤65.0;50.0≤v2≤75.0;18.0≤v3≤26.0;60.0≤v4≤75.0;20.0≤v5≤35.0;50.0≤v6≤60.0;

[0014] Among them, the dispersion coefficient of the first convex-concave lens is v1, the dispersion coefficient of the second biconcave lens is v2, the dispersion coefficient of the third convex-concave lens is v3, the dispersion coefficient of the fourth biconvex lens is v4, the dispersion coefficient of the fifth biconcave lens is v5, and the dispersion coefficient of the sixth biconvex lens is v6.

[0015] Optionally, the second biconcave lens, the third convex-concave lens, the fifth biconcave lens, and the sixth biconvex lens are all plastic aspheric lenses;

[0016] The first convex-concave lens and the fourth biconvex lens are glass spherical lenses.

[0017] Optionally, the effective focal length of the day / night confocal lens is EFL, and the total optical length of the day / night confocal lens is TTL, wherein TTL / EFL≤5.95.

[0018] Optionally, the diameter of the first convex-concave lens is D1, and the total optical length of the day-night confocal lens is TTL, wherein D1 / TTL<0.55.

[0019] Optionally, the image plane diameter IC of the day / night confocal lens satisfies: 6 mm ≤ IC ≤ 7.2 mm.

[0020] Optionally, the day and night confocal lens further includes an aperture, a protective glass and a photosensitive chip from the object side to the image side, wherein the aperture is arranged between the third convex-concave lens and the fourth biconvex lens, and the protective glass and the photosensitive chip are arranged on the side of the sixth biconvex lens close to the image side.

[0021] The present invention also provides an imaging device, which includes the day and night confocal lens.

[0022] In the technical solution provided by the present invention, a first convex-concave lens with negative optical focal length, a second biconcave lens with negative optical focal length, a third convex-concave lens with negative optical focal length, a fourth biconcave lens with positive optical focal length, a fifth biconcave lens with negative optical focal length, and a sixth biconvex lens with positive optical focal length are arranged in sequence from the object side to the image side. Due to the large aperture of the first convex-concave lens, more light information can be collected under the same focal length, achieving the effect of clear imaging in weak light, which can effectively increase the monitoring field of view. The fourth biconvex lens bears the larger optical focal length of the system, changes the propagation direction of the light beam, and is more conducive to the imaging of the light beam on the image plane. Through the reasonable setting of the optical focal length and shape of the six lenses, low cost and lightweight can be achieved. The day and night confocal lens can well control the light trend, introduce more light and make the structure more compact, so that the total length of the day and night confocal lens is controlled within 13 mm, and through the reasonable arrangement of aspheric lenses, various aberrations are corrected, the edge image quality is improved, and the imaging quality is high. In terms of aperture, the aperture value F satisfies 1.8≤F≤2.4, supporting a 1 / 2.7-inch image plane. The day and night confocal lens can also produce clear images in weak light. By reasonably setting the focal length ratio, the lens does not defocus under environmental conditions of -40℃ to +85℃, the working performance is more stable, the field of view angle can reach 195°±5%, and more sufficient data information can be obtained, thereby providing a large aperture, large angle, small high and low temperature day and night confocal lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of the structure of the day and night confocal lens provided by the present invention;

[0025] Figure 2 for Figure 1 Schematic diagram of the spherical aberration curve of the day and night confocal lens;

[0026] Figure 3 for Figure 1 Schematic diagram of the light fan of the day and night confocal lens;

[0027] Figure 4 for Figure 1 Schematic diagram of field distortion / field curvature of day and night confocal lens;

[0028] Figure 5 for Figure 1 MTF diagram of the day and night confocal lens.

[0029] Description of Figure Numbers:

[0030]

[0031]

[0032] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0035] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0036] The current closed-circuit surveillance industry is moving towards miniaturization, multifunctionality, and strong environmental adaptability. However, existing technologies suffer from the following major drawbacks: Due to the complexities of different regional environments, they cannot adapt to large temperature fluctuations, easily causing defocus and affecting the quality of images. Furthermore, when surveillance cameras operate for extended periods, their circuits generate heat, which can affect lens focus under high temperatures. At night or in low-light areas, existing cameras are prone to color loss, blurred details, and insufficient brightness under infrared fill light, resulting in poor image quality. They also suffer from narrow shooting angles and fields of view, resulting in inadequate data collection.

[0037] In order to solve the above problems, the present invention provides a day and night confocal lens. Figures 1 to 5 This is a specific embodiment of the day and night confocal lens provided by the present invention.

[0038] See also Figure 1 The day and night confocal lens has an object side and an image side that are relatively arranged along the optical axis. The day and night confocal lens has an object side and an image side that are relatively arranged along the optical axis. The day and night confocal lens includes a first convex-concave lens 1 with negative optical focal length, a second biconcave lens 2 with negative optical focal length, a third convex-concave lens 3 with negative optical focal length, a fourth biconcave lens 4 with positive optical focal length, a fifth biconcave lens 5 with negative optical focal length, and a sixth biconvex lens 6 with positive optical focal length, which are arranged in sequence from the object side to the image side, and the concave surfaces of the first convex-concave lens 1 and the third convex-concave lens 3 are arranged towards the image side; the total optical length TTL of the day and night confocal lens is ≤13mm, the aperture number of the day and night confocal lens is F, and 1.8≤F≤2.4, and the field of view FOV=195°±5%.

[0039] In the technical solution provided by the present invention, a first convex-concave lens 1 with negative optical focal length, a second biconcave lens 2 with negative optical focal length, a third convex-concave lens 3 with negative optical focal length, a fourth biconcave lens 4 with positive optical focal length, a fifth biconcave lens 5 with negative optical focal length, and a sixth biconvex lens 6 with positive optical focal length are sequentially arranged from the object side to the image side. Due to the large aperture of the first convex-concave lens 1, more light information can be collected under the same focal length, achieving the effect of clear imaging in weak light, and effectively increasing the monitoring field of view. The fourth biconvex lens 4 bears the larger optical focal length of the system, changes the propagation direction of the light beam, and is more conducive to the imaging of the light beam on the image plane. Through the reasonable setting of the optical focal length and shape of the six lenses, low cost and lightweight can be achieved. The day and night confocal lens can well control the light trend, introduce more light and make the structure more compact, so that the total length of the day and night confocal lens is controlled within 13 mm, and through the reasonable arrangement of aspheric lenses, various aberrations are corrected, the edge image quality is improved, and the imaging quality is high. In terms of aperture, the aperture value F satisfies 1.8≤F≤2.4, supporting a 1 / 2.7-inch image plane. The day and night confocal lens can also produce clear images in weak light. By reasonably setting the focal length ratio, the lens does not defocus under environmental conditions of -40℃ to +85℃, the working performance is more stable, the field of view angle can reach 195°±5%, and more sufficient data information can be obtained, thereby providing a large aperture, large angle, small high and low temperature day and night confocal lens.

[0040] Specifically, in this embodiment, the day-night confocal lens further satisfies the following conditions: -4 < f1 < -2; -5.4 < f2 < -4.6; 2.6 < f3 < 4.8; 2.4 < f4 < 4.0; -3.2 < f5 < -1.6; 2.4 < f6 < 3.5. The focal length of the first convex-concave lens 1 is f1, the focal length of the second biconcave lens 2 is f2, the focal length of the third convex-concave lens 3 is f3, the focal length of the fourth biconcave lens 4 is f4, the focal length of the fifth biconcave lens 5 is f5, and the focal length of the sixth biconvex lens 6 is f6. By combining different lenses and rationally allocating their optical power, the optical system achieves excellent performance, including large aperture, wide viewing angle, high pixel count, and excellent athermalization.

[0041] Specifically, in this embodiment, the day and night confocal lens further meets the following conditions:

[0042] 1.60≤n1≤1.80;1.50≤n2≤1.60;1.55≤n3≤1.70;1.50≤n4≤1.70;1.60≤n5≤1.70;1.50≤n6≤1.75;

[0043] Among them, the refractive index of the first convex-concave lens 1 is n1, the refractive index of the second biconcave lens 2 is n2, the refractive index of the third convex-concave lens 3 is n3, the refractive index of the fourth biconvex lens 4 is n4, the refractive index of the fifth biconcave lens 5 is n5, and the refractive index of the sixth biconvex lens 6 is n6.

[0044] Specifically, in an optical lens, the dispersion of light can cause undesirable chromatic aberration, thereby resulting in blur or a blurring effect or "color fringing" around the observed object. In order to ensure that the day and night confocal lens has better imaging quality, in this embodiment, the day and night confocal lens also meets the following conditions:

[0045] 50.0≤v1≤65.0;50.0≤v2≤75.0;18.0≤v3≤26.0;60.0≤v4≤75.0;20.0≤v5≤35.0;50.0≤v6≤60.0;

[0046] Among them, the dispersion coefficient of the first convex-concave lens 1 is v1, the dispersion coefficient of the second biconcave lens 2 is v2, the dispersion coefficient of the third convex-concave lens 3 is v3, the dispersion coefficient of the fourth biconcave lens 4 is v4, the dispersion coefficient of the fifth biconcave lens 5 is v5, and the dispersion coefficient of the sixth biconvex lens 6 is v6. The dispersion coefficient is v7. The dispersion coefficient is used to measure the degree of light dispersion of a transparent medium. The Abbe number is an index used to represent the dispersion ability of a transparent medium. The larger the dispersion coefficient (Abbe number), the less obvious the dispersion and the better the imaging quality of the lens. In this embodiment, the dispersion coefficient of each lens is controlled at a higher value, so that the dispersion of the day and night confocal lens is not obvious and the imaging quality of the lens is good.

[0047] Specifically, because resin lenses have strong impact resistance, light weight, and low cost, in this embodiment, the second biconcave lens 2, the third convex-concave lens 3, the fifth biconcave lens 5, and the sixth biconvex lens 6 are all plastic aspheric lenses; by adopting plastic aspheric lenses, costs are effectively controlled, and the aspheric lenses can well correct lens chromatic aberration, while ensuring that the purple fringe of the lens is controlled, the spherical aberration and sine difference at the high-magnification position are corrected at the same time.

[0048] However, due to the chemical instability of plastic materials affected by ambient temperature, their refractive index is weaker than that of all-glass lenses, resulting in inferior image reproduction. To ensure the stability of the video lens under temperature fluctuations, in this embodiment, the first convex-concave lens 1 and the fourth biconvex lens 4 are glass spherical lenses. Because glass lenses are less susceptible to thermal expansion and contraction, which can cause focus shifts, they can effectively resist thermal deformation and maintain high lens precision over time. The day-night confocal lens utilizes a glass-plastic hybrid material, which not only saves costs and provides strong impact resistance, but also ensures system stability and high and low temperature compatibility.

[0049] Specifically, in this embodiment, the effective focal length of the day / night confocal lens is EFL, and the total optical length is TTL, where TTL / EFL ≤ 5.95. By combining different lenses and rationally allocating optical power, the lens achieves excellent performance, including day / night confocality, a wide viewing angle, high pixel count, and excellent athermalization. It should be noted that the effective focal length (EFL) refers to the distance between the center vertex of the object-side side of the first lens and the imaging plane on the optical axis, while the total optical length (TTL) is the distance from the center vertex of the object-side side of the first lens to the imaging plane.

[0050] Specifically, in this embodiment, the diameter of the first convex-concave lens 1 is D1, and the total optical length of the day-night confocal lens is TTL, where D1 / TTL < 0.55. When D1 and TTL satisfy this relationship, the lens aperture can be prevented from being too large, meeting the installation space requirements of the final product.

[0051] Specifically, in this embodiment, the image plane diameter IC of the day / night confocal lens satisfies: 6 mm ≤ IC ≤ 7.2 mm.

[0052] Furthermore, in this embodiment, the day and night confocal lens further includes an aperture 7, a protective glass 8 and a photosensitive chip 9 from the object side to the image side. The aperture 7 is arranged between the third convex-concave lens 3 and the fourth biconvex lens 4, and the protective glass 8 and the photosensitive chip 9 are arranged on the side of the sixth biconvex lens 6 close to the image side. Since the aperture 7 is used to adjust the light flux according to actual conditions, the imaging quality can be improved. The protective glass 8 can provide effective protection for the photosensitive chip 9IMAGE. The protective glass 8 can be set as a filter. The filter can effectively filter out stray light in non-working bands to reduce optical noise, reduce difficulties for the subsequent photoelectric module processing part, and thus improve imaging quality. It can be understood that the surface of the photosensitive chip 9 facing the object side is the imaging surface.

[0053] Specifically, the imaging surface can be understood as the surface of the photosensitive chip 9 facing the object side, that is, it can be the surface of a camera element such as a CCD or CMOS. It can be understood that the light carrying the information of the object can pass through the first convex-concave lens 1, the second biconcave lens 2, the third convex-concave lens 3, the fourth biconvex lens 4, the fifth biconcave lens 5 and the sixth biconvex lens 6 in sequence and finally form an image on the imaging surface.

[0054] Specifically, in this embodiment, the parameters of the day and night confocal lens are as follows:

[0055] The day / night confocal lens of this embodiment has a focal length of f=2.3 mm, an aperture value of F=2.06, an image plane diameter of 6.9 mm, and a diagonal field of view of 195°.

[0056] Specifically, in this embodiment, the refractive index, curvature radius, and thickness interval of the lens material are shown in Table 1 below:

[0057] Table 1

[0058]

[0059] Specifically, in this embodiment, the first convex-concave lens 1, the second biconcave lens 2, the third convex-concave lens 3, the fifth biconcave lens 5 and the sixth biconvex lens 6 are all aspherical lenses, and the characteristics of aspherical lenses are: the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike spherical lenses with a constant curvature from the center of the lens to the periphery of the lens, aspherical lenses have better curvature radius characteristics and have the advantages of improving distortion aberration and improving astigmatism aberration. After using aspherical lenses, the aberrations that occur during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens, and the use of glass lenses can reduce the impact of temperature on the optical performance of the lens.

[0060] Furthermore, in this embodiment, the aspheric surface shape of the aspheric lens satisfies the following conditions:

[0061]

[0062] Where c is the curvature corresponding to the radius, y is the radial coordinate (its unit is the same as the lens length unit), k is the conic coefficient (when the k coefficient is less than -1, the surface curve is a hyperbola, when the k coefficient is equal to -1, it is a parabola, when the k coefficient is between -1 and 0, it is an ellipse, when the k coefficient is equal to 0, it is a circle, and when the k coefficient is greater than 0, it is an oblate), the 4th-order term, 6th-order term, 8th-order term, 10th-order term, 12th-order term, 14th-order term, and 16th-order term represent higher-order aspheric coefficients (see Table 2 below), respectively. The above parameters can be used to set the shape and size of the lens object side and image side aspheric surfaces.

[0063] Table 2 Conic coefficients and aspheric coefficients corresponding to aspheric lenses:

[0064]

[0065] Figure 2 This is a schematic diagram of a spherical aberration curve of an embodiment of a day and night confocal lens provided by the present invention. Figure 3 A schematic diagram of a light fan of an embodiment of a day-night confocal lens provided by the present invention.

[0066] Figure 4 A schematic diagram of field distortion and curvature of field for an embodiment of a day / night confocal lens provided by the present invention. S and T in the figure represent the aberrations corresponding to the sagittal and meridional image sides, respectively. The left side shows the field curvature diagram, and the right side shows the distortion diagram.

[0067] Figure 5 This is a schematic diagram of the MTF of an embodiment of a day / night confocal lens provided by the present invention. The abscissa is spatial frequency, and the ordinate is contrast. TS Diff. Limit is the diffraction limit in the tangential and sagittal directions, and TS 0.00 (deg) represents the diffraction curve in the tangential and sagittal directions at a field of view of 0.00 on the image plane.

[0068] As can be seen from the above figures, the spherical aberration, field curvature and distortion of the day and night confocal lens in this embodiment can all be well corrected.

[0069] In summary, the aperture value F of the day and night confocal lens satisfies 1.8≤F≤2.4, supports a 1 / 2.7-inch image plane, does not defocus under environmental conditions of -40℃ to +85℃, has a field of view angle of up to 190°±5%, and the total length of the lens is controlled within 13mm.

[0070] The present invention also provides an imaging device, which can be an electronic device such as a camera, a monitoring device, or a camera. The imaging device includes the day-night confocal lens described in the above technical solution. The specific structure of the day-night confocal lens refers to the above embodiments. Since the day-night confocal lens of the present day-night confocal lens adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0071] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A day and night confocal lens, characterized in that: The day-night confocal lens has an object side and an image side arranged opposite to each other along the optical axis, and includes a first convex-concave lens with negative optical power, a second biconcave lens with negative optical power, a third biconvex lens with positive optical power, a fourth biconvex lens with positive optical power, a fifth biconcave lens with negative optical power, and a sixth biconvex lens with positive optical power, which are arranged in sequence from the object side to the image side, and the concave surfaces of the first convex-concave lens and the third biconvex lens are arranged toward the image side; The total optical length TTL of the day and night confocal lens is ≤ 13 mm, the aperture number of the day and night confocal lens is F, and 1.8≤F≤2.4, and the field of view FOV = 195°±5%; The day and night confocal lens also meets the following conditions: -4mm<f1<-2mm; -5.4mm<f2<-4.6mm; 2.6mm<f3<4.8mm; 2.4mm<f4<4.0mm; -3.2mm<f5<-1.6mm; 2.4mm<f6<3.5mm; Among them, the focal length of the first convex-concave lens is f1, the focal length of the second biconcave lens is f2, the focal length of the third biconvex lens is f3, the focal length of the fourth biconvex lens is f4, the focal length of the fifth biconcave lens is f5, and the focal length of the sixth biconvex lens is f6.

2. The day and night confocal lens according to claim 1, wherein: The day and night confocal lens also meets the following conditions: 1.60≤n1≤1.80;1.50≤n2≤1.60;1.55≤n3≤1.70;1.50≤n4≤1.70;1.60≤n5≤1.70;1.50≤n6≤1.75; Among them, the refractive index of the first convex-concave lens is n1, the refractive index of the second biconcave lens is n2, the refractive index of the third biconvex lens is n3, the refractive index of the fourth biconvex lens is n4, the refractive index of the fifth biconcave lens is n5, and the refractive index of the sixth biconvex lens is n6.

3. The day and night confocal lens according to claim 1, wherein: The day and night confocal lens also meets the following conditions: 50.0≤v1≤65.0;50.0≤v2≤75.0;18.0≤v3≤26.0;60.0≤v4≤75.0;20.0≤v5≤35.0;50.0≤v6≤60.0; Among them, the dispersion coefficient of the first convex-concave lens is v1, the dispersion coefficient of the second biconcave lens is v2, the dispersion coefficient of the third biconvex lens is v3, the dispersion coefficient of the fourth biconvex lens is v4, the dispersion coefficient of the fifth biconcave lens is v5, and the dispersion coefficient of the sixth biconvex lens is v6.

4. The day and night confocal lens according to claim 1, wherein: The second biconcave lens, the third biconvex lens, the fifth biconcave lens, and the sixth biconvex lens are all plastic aspheric lenses; The first convex-concave lens and the fourth biconvex lens are glass spherical lenses.

5. The day and night confocal lens according to claim 1, wherein: The effective focal length of the day-night confocal lens is EFL, and the total optical length of the day-night confocal lens is TTL, wherein TTL / EFL≤5.

95.

6. The day and night confocal lens according to claim 1, wherein: The diameter of the first convex-concave lens is D1, and the total optical length of the day-night confocal lens is TTL, wherein D1 / TTL<0.

55.

7. The day and night confocal lens according to claim 1, wherein: The image plane diameter IC of the day-night confocal lens satisfies: 6 mm ≤ IC ≤ 7.2 mm.

8. The day and night confocal lens according to claim 1, wherein: The day and night confocal lens further includes an aperture, a protective glass and a photosensitive chip from the object side to the image side, wherein the aperture is arranged between the third biconvex lens and the fourth biconvex lens, and the protective glass and the photosensitive chip are arranged on the side of the sixth biconvex lens close to the image side.

9. An imaging device, characterized in that: The day / night confocal lens according to any one of claims 1 to 8.

Images