Large-target-surface high-pixel high-resolution security lens

Abstract

The utility model discloses a large-target-surface high-pixel high-resolution security lens. A spherical glass first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens are sequentially arranged from the object side to the image side along the optical axis of the lens, the second aspheric plastic lens has positive focal power or negative focal power; the third aspheric plastic lens has positive focal power; the spherical glass fourth lens has positive focal power; the fifth aspheric plastic lens has positive focal power; the aspheric plastic sixth lens has negative focal power; and the aspheric plastic seventh lens has positive focal power. The optical lens provided by the utility model is high in resolution, can be matched with a high-pixel chip, and has the advantages of large-target-surface imaging, higher relative illumination, capability of realizing day and night confocal in high and low temperature environments, and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of optical lenses, in particular to a large target surface, high pixel and high resolution security lens. Background Art

[0002] With the continuous expansion and extension of the monitoring system in various application fields, more and more security monitoring lenses are used in various occasions and working environments. Therefore, higher requirements are put forward for the pixel resolution, working environment temperature, etc. of the security monitoring lenses.

[0003] However, the current security monitoring lenses still have many deficiencies. For example, the resolution of the lens is not high, especially in the large target surface area, the resolution is even worse; the chromatic aberration of the lens is large, which is easy to cause blue-violet edges; the operating temperature range of the lens is relatively narrow, and it is easy to defocus when working in high and low temperature environments; the light transmission of the lens is small, and the illuminance is low, and the low-light effect is not good, etc. Summary of the Utility Model

[0004] Based on this, the purpose of the utility model is to provide a large target surface, high pixel and high resolution security lens, which adopts 2 glass spherical lenses and 5 plastic aspherical lenses, the total length of the lens ≤ 22.5 mm, the aperture F# ≥ 1.6, and can be matched with a 1 / 1.8-inch large target surface chip, which can meet the current market demand for large target surface, high pixel and high resolution of security monitoring lenses.

[0005] The purpose of the utility model is realized through the following technical solutions:

[0006] A large target surface, high pixel and high resolution security lens, defining the surface on the side of the lens adjacent to the object surface as the object side surface, and the surface on the side of the lens adjacent to the image surface as the image side surface, characterized in that: along the optical axis of the lens, from the object side to the image side, they are arranged in sequence:

[0007] A first lens, the first lens is a spherical glass lens with negative optical power, its object side surface is convex, and its image side surface is concave;

[0008] A second lens, the second lens is an aspherical plastic lens that can be either positive or negative optical power, its object side surface is concave, and its image side surface is convex;

[0009] A third lens, the third lens is an aspherical plastic lens with positive optical power, its object side surface is convex, and its image side surface is concave;

[0010] A diaphragm, the diaphragm is located between the image side surface of the third lens and the object side surface of the fourth lens;

[0011] A fourth lens, the fourth lens is a spherical glass lens with positive optical power, its object side surface is convex, and its image side surface is convex;

[0012] The fifth lens, which is an aspherical plastic lens with positive optical power, has a convex object side and a convex image side;

[0013] The sixth lens, which is an aspherical plastic lens with negative optical power, has a concave object side and a concave image side;

[0014] The seventh lens, which is an aspherical plastic lens with positive optical power, has a convex object side and a concave image side;

[0015] A filter, which is disposed on the image side of the seventh lens;

[0016] A protective glass and an image acquisition element, where the protective glass is integrated on the image acquisition element, and the image acquisition element is disposed on the image side of the protective glass.

[0017] Furthermore, the lens satisfies the following relational expressions:

[0018] -1.71 ≤ f1 / f ≤ -1.42;

[0019] -3.22 ≤ f2 / f ≤ 32.98;

[0020] 6.78 ≤ f3 / f ≤ 60.16;

[0021] 1.39 ≤ f4 / f ≤ 1.7;

[0022] 1.63 ≤ f5 / f ≤ 2.14;

[0023] -1.53 ≤ f6 / f ≤ -1.37;

[0024] 2.05 ≤ f7 / f ≤ 2.66;

[0025] In the relational expressions, f is the total focal length of the optical 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, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.

[0026] Furthermore, the lens also satisfies the following relational expressions:

[0027] IC / TTL ≥ 0.39;

[0028] TTL / f ≤ 5.21;

[0029] OBFL / TTL ≥ 0.21;

[0030] In the relational expression, f is the total focal length of the optical lens, TTL is the total length of the lens optical system, OBFL is the optical back focal length of the lens system, that is, the distance from the point on the image side of the seventh lens closest to the image plane to the image plane, IC is the full image height of the chip matched with the lens system, and the maximum can match a 1 / 1.8-inch target chip.

[0031] Further, the aperture of the optical lens is F#, satisfying F#≥1.6;

[0032] The total focal length of the optical lens is f, satisfying f≥4.3mm;

[0033] The total length of the lens optical system is TTL, satisfying TTL≤22.5mm.

[0034] Further, the focal lengths, refractive indices, and curvature radii of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens respectively satisfy the following conditions:

[0035] f1 -7.62～-6.81 ND1 1.50～1.54 R11 +67.8～+200.06 R12 +3.46～+3.79 f2 -147.4～+166.21 ND2 1.51～1.57 R21 -3.93～-3.3 R22 -8.7～-4.41 f3 +29.3～+303.18 ND3 1.60～1.68 R31 +5.52～+6.25 R32 +5.05～+7.51 f4 +7.0～+7.34 ND4 1.45～1.55 R41 +6.37～+6.61 R42 -6.61～-6.37 f5 +7.48～+10.82 ND5 1.51～1.57 R51 +7.88～+16.88 R52 -8.45～-6.89 f6 -7.54～-5.92 ND6 1.60～1.68 R61 -2.96～-2.2 R62 -10.86～-5.93 f7 +8.71～+13.12 ND7 1.51～1.57 R71 +3.35～+4.0 R72 +5.62～+13.68

[0036] In the above table, where f1 is the focal length of the first lens, ND1 is the refractive index of the first lens, R11 is the curvature radius of the object side of the first lens, and R12 is the curvature radius of the image side of the first lens;

[0037] f2 is the focal length of the second lens, ND2 is the refractive index of the second lens, R21 is the curvature radius of the object side of the second lens, and R22 is the curvature radius of the image side of the second lens;

[0038] f3 is the focal length of the third lens, ND3 is the refractive index of the third lens, R31 is the curvature radius of the object side of the third lens, and R32 is the curvature radius of the image side of the third lens;

[0039] f4 is the focal length of the fourth lens, ND4 is the refractive index of the fourth lens, R41 is the curvature radius of the object side of the fourth lens, and R42 is the curvature radius of the image side of the fourth lens;

[0040] f5 is the focal length of the fifth lens, ND5 is the refractive index of the fifth lens, R51 is the curvature radius of the object side of the fifth lens, and R52 is the curvature radius of the image side of the fifth lens;

[0041] f6 is the focal length of the sixth lens, ND6 is the refractive index of the sixth lens, and R61 is the curvature radius of the object side of the sixth lens;

[0042] f7 is the focal length of the seventh lens, ND7 is the refractive index of the seventh lens, R71 is the curvature radius of the object side of the seventh lens, and R72 is the curvature radius of the image side of the seventh lens;

[0043] Focal length: The "+" sign indicates that the lens has a positive optical power, and the "-" sign indicates that the lens has a negative optical power, with the unit of mm;

[0044] Radius of curvature: The "+" sign indicates that the surface bends towards the image side, and the "-" sign indicates that the surface bends towards the object side, with the unit of mm.

[0045] Furthermore, the aspherical surfaces of the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens can all be defined by the following equation of even-order aspherical surface:

[0046]

[0047] In the formula, Z is the sagittal height of the lens along the optical axis direction, k is the conic coefficient of the quadratic surface, r is the lens height, c is the lens curvature, and A, B, C, D, E, F, G are the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial.

[0048] The beneficial effects of the present utility model are:

[0049] The present utility model adopts a hybrid combination of 2 spherical glass lenses and 5 aspherical plastic lenses. Through the mutual matching of different lens shapes and reasonable optical power distribution, the lens has good optical performance, a compact structure, and is not bulky.

[0050] In terms of performance, the 5 aspherical lenses can effectively correct the system aberration, ensure the system optical performance, and enable the lens to achieve day-night confocal on a large target surface chip; the entire optical system meets the requirements of aperture F#≥1.6, has a large light transmission aperture, and focal length f≥4mm. Therefore, it can ensure good relative illumination of the edge field of view of the system, making the brightness of the picture edge uniform without vignetting during shooting; it can match a 1 / 1.8-inch chip at most, thereby meeting the requirements of higher pixels.

[0051] In terms of materials, the first lens uses glass material. Compared with plastic, glass material has better light transmittance, can enable light to enter the lens as much as possible, thereby improving the imaging quality; at the same time, glass material has better stability in chemical and physical properties and a longer service life.

[0052] In terms of structure, through the cooperation of different materials and reasonable optical power of the lenses, the lens can achieve clear real-time shooting images at high temperature +70°C and low temperature -30°C; the structure between the lenses is compact, with the characteristics of small volume, light weight, and good performance. Description of the Drawings

[0053] Figure 1 It is a schematic optical structure diagram of Embodiment 1 of the present utility model;

[0054] Figure 2 It is a schematic light path structure diagram of Embodiment 1 of the present utility model;

[0055] Figure 3 This is the MTF curve graph of visible light with wavelengths of 0.435 - 0.656 μm (200 lp / mm) in Embodiment 1 of the present utility model;

[0056] Figure 4 This is the MTF curve graph of infrared light with a wavelength of 0.850 μm (200 lp / mm) in Embodiment 1 of the present utility model;

[0057] Figure 5 This is the defocus curve graph of visible light with wavelengths of 0.435 - 0.656 μm (125 lp / mm) at a high temperature of +70°C in Embodiment 1 of the present utility model;

[0058] Figure 6 This is the defocus curve graph of visible light with wavelengths of 0.435 - 0.656 μm (125 lp / mm) at a low temperature of -30°C in Embodiment 1 of the present utility model;

[0059] Figure 7 This is the relative illuminance graph of visible light with a wavelength of 0.546 μm in Embodiment 1 of the present utility model;

[0060] Figure 8 This is the schematic optical structure diagram of Embodiment 2 of the present utility model;

[0061] Figure 9 This is the schematic optical path structure diagram of Embodiment 2 of the present utility model;

[0062] Figure 10 This is the MTF curve graph of visible light with wavelengths of 0.435 - 0.656 μm (200 lp / mm) in Embodiment 2 of the present utility model;

[0063] Figure 11 This is the MTF curve graph of infrared light with a wavelength of 0.850 μm (200 lp / mm) in Embodiment 2 of the present utility model;

[0064] Figure 12 This is the defocus curve graph of visible light with wavelengths of 0.435 - 0.656 μm (125 lp / mm) at a high temperature of +70°C in Embodiment 2 of the present utility model;

[0065] Figure 13 This is the defocus curve graph of visible light with wavelengths of 0.435 - 0.656 μm (125 lp / mm) at a low temperature of -30°C in Embodiment 2 of the present utility model;

[0066] Figure 14 This is the relative illuminance graph of visible light with a wavelength of 0.546 μm in Embodiment 2 of the present utility model;

[0067] Reference numerals: 1 - first lens, 2 - second lens, 3 - third lens, 4 - fourth lens, 5 - fifth lens, 6 - sixth lens, 7 - seventh lens, 8 - aperture stop, 9 - filter, 10 - protective glass, 11 - image acquisition element. Detailed implementation

[0068] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. In this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. The shape of the spherical or aspherical surface is not limited to the spherical or aspherical shape shown in the accompanying drawings. The accompanying drawings are only for illustration and are not drawn strictly to scale.

[0069] In the present utility model, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region; if the lens surface is not defined as convex, concave or flat, it means that the lens surface can be convex, concave or flat. The surface of each lens closest to the object to be photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0070] Unless otherwise defined, all terms (including technical terms and scientific terms) used in the present utility model have the same meaning as the ordinary understanding of those of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless clearly defined in the present utility model.

[0071] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present utility model. For better understanding and implementation, the present utility model will be described in detail below with reference to the accompanying drawings.

[0072] An embodiment of the present utility model provides a large target surface, high pixel, and high resolution security lens. The surface of the lens adjacent to the object side is the object side surface, and the surface of the lens adjacent to the image side is the image side surface. Along the optical axis of the lens, a first lens 1, a second lens 2, a third lens 3, an aperture stop 8, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, a filter 9, a protective glass 10, and an image acquisition element 11 are sequentially arranged from the object side to the image side. The aperture stop 8 is located between the third lens 3 and the fourth lens 4. The filter 9 is arranged on the image side surface of the seventh lens 7. The image acquisition element 11 is arranged on the image side surface of the protective glass 10, and the protective glass 10 is integrated on the image acquisition element 11.

[0073] Among them:

[0074] The first lens 1 is a spherical glass lens with a negative optical power. Its object side surface is convex, and its image side surface is concave.

[0075] The second lens 2 is an aspherical plastic lens with a positive or negative optical power. Its object side surface is concave, and its image side surface is convex.

[0076] The third lens 3 is an aspherical plastic lens with a positive optical power. Its object side surface is convex, and its image side surface is concave.

[0077] The fourth lens 4 is a spherical glass lens with a positive optical power. Its object side surface is convex, and its image side surface is convex.

[0078] The fifth lens 5 is an aspherical plastic lens with a positive optical power. Its object side surface is convex, and its image side surface is convex.

[0079] The sixth lens 6 is an aspherical plastic lens with a negative optical power. Its object side surface is concave, and its image side surface can be concave.

[0080] The seventh lens 7 is an aspherical plastic lens with a positive optical power. Its object side surface is convex, and its image side surface can be concave.

[0081] The total focal length of the optical system of the lens of the present utility model is f, the total optical length of the lens system is TTL, and the optical back focal length of the lens system is OBFL, that is, the distance from the point on the image side surface of the seventh lens 7 closest to the image plane to the image plane. The full image height of the chip matched by the lens system is IC. The lens can maximally match a 1 / 1.8-inch chip to achieve large target surface and high pixel imaging. They satisfy the following relationships: IC / TTL ≥ 0.39; TTL / f ≤ 5.21; OBFL / TTL ≥ 0.21.

[0082] In the present utility model, the aperture of the lens is F#, satisfying F# ≥ 1.6;

[0083] The field of view of the lens is FOV, satisfying FOV ≥ 105°;

[0084] The total length of the lens is TTL, satisfying TTL ≤ 22.5 mm;

[0085] The total focal length of the lens optical system is f, satisfying f ≥ 4.3 mm;

[0086] The optical back focal length of the lens is OBFL, satisfying OBFL ≥ 4.8 mm.

[0087] In the present utility model, in order to enable the optical system to exhibit better performance, during the design process, we need to reasonably select the lens material, reasonably distribute the focal lengths of each lens, and reasonably optimize the optical system to correct the aberrations of the system, and finally optimize the performance of the optical system. f is the total focal length of the optical lens, and the ratio of the focal length of each lens to the total focal length of the lens satisfies the following conditions:

[0088] -1.71 ≤ f1 / f ≤ -1.42;

[0089] -3.22 ≤ f2 / f ≤ 32.98;

[0090] 6.78 ≤ f3 / f ≤ 60.16;

[0091] 1.39 ≤ f4 / f ≤ 1.7;

[0092] 1.63 ≤ f5 / f ≤ 2.14;

[0093] -1.53 ≤ f6 / f ≤ -1.37;

[0094] 2.05 ≤ f7 / f ≤ 2.66.

[0095] The focal lengths, refractive indices, and curvature radii of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, and the tenth lens 10 respectively satisfy the following conditions:

[0096] f1 -7.62～-6.81 ND1 1.50～1.54 R11 +67.8～+200.06 R12 +3.46～+3.79 f2 -147.4～+166.21 ND2 1.51～1.57 R21 -3.93～-3.3 R22 -8.7～-4.41 f3 +29.3～+303.18 ND3 1.60～1.68 R31 +5.52～+6.25 R32 +5.05～+7.51 f4 +7.0～+7.34 ND4 1.45～1.55 R41 +6.37～+6.61 R42 -6.61～-6.37 f5 +7.48～+10.82 ND5 1.51～1.57 R51 +7.88～+16.88 R52 -8.45～-6.89 f6 -7.54～-5.92 ND6 1.60～1.68 R61 -2.96～-2.2 R62 -10.86～-5.93 f7 +8.71～+13.12 ND7 1.51～1.57 R71 +3.35～+4.0 R72 +5.62～+13.68

[0097] In the above table, where f1 is the focal length of the first lens, ND1 is the refractive index of the first lens, R11 is the curvature radius of the object side surface of the first lens, and R12 is the curvature radius of the image side surface of the first lens;

[0098] f2 is the focal length of the second lens, ND2 is the refractive index of the second lens, R21 is the curvature radius of the object side surface of the second lens, and R22 is the curvature radius of the image side surface of the second lens;

[0099] f3 is the focal length of the third lens, ND3 is the refractive index of the third lens, R31 is the curvature radius of the object side surface of the third lens, and R32 is the curvature radius of the image side surface of the third lens;

[0100] f4 is the focal length of the fourth lens, ND4 is the refractive index of the fourth lens, R41 is the curvature radius of the object side surface of the fourth lens, and R42 is the curvature radius of the image side surface of the fourth lens;

[0101] f5 is the focal length of the fifth lens, ND5 is the refractive index of the fifth lens, R51 is the curvature radius of the object side surface of the fifth lens, and R52 is the curvature radius of the image side surface of the fifth lens;

[0102] f6 is the focal length of the sixth lens, ND6 is the refractive index of the sixth lens, and R61 is the curvature radius of the object side surface of the sixth lens;

[0103] f7 is the focal length of the seventh lens, ND7 is the refractive index of the seventh lens, R71 is the curvature radius of the object side surface of the seventh lens, and R72 is the curvature radius of the image side surface of the seventh lens;

[0104] Focal length: The "+" sign indicates that the lens has a positive optical power, and the "-" sign indicates that the lens has a negative optical power, with the unit of mm;

[0105] Curvature radius: The "+" sign indicates that the surface bends towards the image side, and the "-" sign indicates that the surface bends towards the object side, with the unit of mm.

[0106] In the present utility model, the aspherical surfaces of the second lens 2, the third lens 3, the fifth lens 5, the sixth lens 6, and the seventh lens 7 can all be defined by the following equation of even aspherical surfaces:

[0107]

[0108] In the formula, Z is the sag height of the lens along the optical axis direction, k is the conic coefficient of the quadric surface, r is the lens height, c is the lens curvature, and A, B, C, D, E, F, G are the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspherical polynomial.

[0109] The data of the specific embodiments in the specific implementation manner of the present utility model are summarized as shown in Table 1 below:

[0110] Table 1

[0111] Conditional Example 1 Example 2 -1.71 ≤ f1 / f ≤ -1.42 -1.51 -1.63 -3.22 ≤ f2 / f ≤ 32.98 32.98 -3.22 6.78 ≤ f3 / f ≤ 60.16 60.16 6.78 1.39 ≤ f4 / f ≤ 1.7 1.39 1.7 1.63 ≤ f5 / f ≤ 2.14 2.14 1.73 -1.53 ≤ f6 / f ≤ -1.37 -1.38 -1.37 2.05 ≤ f7 / f ≤ 2.66 2.12 2.17

[0112] Example 1

[0113] Reference Figure 1 、 Figure 2As shown, they are respectively the schematic diagram of the optical structure and the optical path structure of Embodiment 1. In this embodiment, the lens field of view FOV = 105°, the lens aperture value F# = 1.6, the total focal length f of the lens optical system = 5 mm, the total optical length TTL of the lens = 22.5 mm, the optical back focal length OBFL of the lens = 4.8 mm, and the lens can be maximally matched with a 1 / 1.8-inch chip.

[0114] In the lens of this embodiment, along the optical axis of the lens, from the object side to the image side, they are arranged in sequence as follows:

[0115] The first lens 1, the first lens 1 is a spherical glass lens with a negative optical power, its object side is a convex surface, and its image side is a concave surface;

[0116] The second lens 2, the second lens 2 is an aspherical plastic lens with a positive optical power, its object side is a concave surface, and its image side is a convex surface;

[0117] The third lens 3, the third lens 3 is an aspherical plastic lens with a positive optical power, its object side is a convex surface, and its image side is a concave surface;

[0118] The aperture stop 8, the aperture stop is located between the image side of the third lens 3 and the object side of the fourth lens 4;

[0119] The fourth lens 4, the fourth lens 4 is a spherical glass lens with a positive optical power, its object side is a convex surface, and its image side is a convex surface;

[0120] The fifth lens 5, the fifth lens 5 is an aspherical plastic lens with a positive optical power, its object side is a convex surface, and its image side is a convex surface;

[0121] The sixth lens 6, the sixth lens 6 is an aspherical plastic lens with a negative optical power, its object side is a concave surface, and its image side can be a concave surface;

[0122] The seventh lens 7, the seventh lens 7 is an aspherical plastic lens with a positive optical power, its object side is a convex surface, and its image side can be a concave surface;

[0123] The filter 9, the filter is arranged on the image side of the seventh lens;

[0124] The protective glass 10 and the image acquisition element 11, the protective glass 10 is integrated on the image acquisition element 11, and the image acquisition element 11 is arranged on the image side of the protective glass 10.

[0125] In this embodiment, the first lens 1 is a spherical glass lens with a negative optical power. Its object side is convex and its image side is concave, forming a meniscus lens with a negative optical power. Its function is to deflect light so that the light enters the optical system. The second lens 2 is an aspherical plastic lens with a positive optical power. Its object side is concave and its image side is convex. Its main function is to converge and adjust the light so that the light enters the optical system smoothly. The third lens 3 is an aspherical plastic lens with a positive optical power. Its object side is convex and its image side is concave. Its function is to correct the spherical aberration of the previous lens and converge the light so that the light fills the pupil. The fourth lens 4 is a biconvex spherical glass lens with a positive optical power, and its Abbe number is greater than 80, which can reduce the defocus shift in the infrared band and improve the resolution in the infrared band. The fifth lens 5 is a biconvex aspherical plastic lens with a positive optical power, and its function is to converge the light and balance the aberration of the front and rear lenses. The sixth lens 6 is an aspherical plastic lens with a negative optical power. Its object side is concave and its image side is concave. Its main function is to diverge the light, expand the imaging surface, and make the system have a larger target surface. The object side of the seventh lens 7 is convex and its image side is concave. Its main function is to control the incident angle of the chief ray and improve the resolution of the system.

[0126] In this embodiment, the radius of curvature (unit: mm), central thickness d (unit: mm), refractive index (ND), Abbe constant (VD), and aspherical K value (Conic) of the first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6, seventh lens 7, eighth lens 8, ninth lens 9, and tenth lens 10 are shown in Table 2.

[0127] Table 2

[0128] Surface number Radius of curvature R Central thickness d Refractive index ND Abbe number VD K 1 67.81 0.85 1.52 64.2 0.00 2 3.72 2.54 0.00 3 -3.93 1.95 1.54 55.7 0.17 4 -4.41 0.07 0.23 5 5.73 2.11 1.64 23.9 -1.01 6 5.05 0.79 1.65 7 (diaphragm) Infinity -0.51 0.00 8 6.38 3.35 1.50 81.6 0.00 9 -6.38 0.09 0.00 10 16.87 2.32 1.54 55.7 -36.86 11 -8.45 0.28 1.19 12 -2.95 1.92 1.64 23.9 -5.22 13 -10.86 0.07 -1.17 14 3.83 1.67 1.54 55.7 -5.74 15 9.74 0.43 -19.53 16 Infinity 0.21 1.52 64.2 0.00 17 Infinity 3.8 0.00

[0129] In Table 2, the surface numbers are numbered according to the surface order of each lens. Among them, "1" represents the front surface of the first lens, "2" represents the rear surface of the first lens, and so on. The radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface bends towards the image side, and a negative value represents that the surface bends towards the object side. Among them, "Infinity" represents that the surface is a plane. The thickness represents the central axial distance from the current surface to the next surface. The refractive index represents the light deflection ability of the current lens material. The Abbe number represents the light dispersion characteristic of the current lens material. The K value represents the numerical value of the best-fit conic coefficient of the aspherical surface.

[0130] The aspherical surfaces of the second lens 2, third lens 3, fifth lens 5, sixth lens 6, and seventh lens 7 in this embodiment can all be defined by the above equation of the even aspherical surface. Table 3 gives the coefficients of the aspherical surfaces of each optical surface.

[0131] Table 3

[0132] Surface number A B C D E F G 3 5.49E-03 -1.70E-04 1.83E-05 -7.36E-07 4.02E-09 9.61E-09 -3.41E-10 4 5.22E-03 -2.13E-04 1.35E-05 2.02E-07 -1.40E-08 -3.35E-09 3.21E-10 5 9.40E-05 8.45E-05 1.28E-08 -4.05E-08 3.80E-08 -4.64E-09 1.83E-10 6 -5.43E-03 6.52E-04 -7.10E-05 1.89E-06 2.77E-07 -1.26E-08 -2.93E-09 10 -1.80E-03 -3.24E-05 1.36E-05 -2.85E-07 -5.54E-08 2.43E-08 -1.03E-09 11 -4.00E-04 -4.46E-04 1.04E-05 2.79E-06 2.01E-07 -2.06E-08 2.30E-10 12 2.96E-03 -5.33E-04 3.03E-05 -1.52E-06 -3.48E-09 5.37E-08 -4.43E-09 13 5.78E-03 1.10E-05 -9.45E-07 -5.07E-07 -2.19E-08 7.26E-09 -4.05E-10 14 -1.70E-03 2.10E-04 -1.66E-05 1.39E-06 -6.47E-08 1.27E-09 -1.08E-11 15 -2.60E-03 9.18E-05 -2.82E-06 -4.14E-08 8.30E-09 3.19E-10 -2.78E-11

[0133] Reference Figure 3 As shown, the MTF curve graphs of different fields of view of the lens in this embodiment at a visible light wavelength of 0.435 - 0.656 μm and a spatial frequency of 200 lp / mm are presented. Among them, the horizontal axis represents the spatial frequency, and the vertical axis represents the MTF value. It can be seen from the figure that when the spatial frequency is 200 lp / mm, the MTF values of the full field of view of the lens are all above 0.3, indicating that this lens has high resolving power and can match chips with higher pixels.

[0134] Reference Figure 4 As shown, the MTF curve graph of the lens in this embodiment at an infrared wavelength of 0.85 μm and a spatial frequency of 200 lp / mm is presented. It can be seen from the figure that when the spatial frequency is 200 lp / mm, the MTF values of the full field of view of the lens are all 0.2 and above, and the MTF value of the central field of view is above 0.3, ensuring that the picture is clear when the lens is used for night shooting and realizing all-weather high-definition monitoring.

[0135] Reference Figure 5 and Figure 6 As shown, the MTF defocus curve graphs of the lens in this embodiment at a visible light wavelength of 0.435 - 0.656 μm and a spatial frequency of 125 lp / mm at high temperature +70 °C and low temperature -30 °C are presented respectively. It can be seen from the figure that at high temperature +70 °C and low temperature -30 °C, the defocus amount is less than 3 μm, ensuring that the lens has high resolving power at high temperature +70 °C and low temperature -30 °C and realizing high-definition picture shooting.

[0136] Reference Figure 7 As shown, the relative illuminance curve graph of the lens in this embodiment at a visible light of 0.546 μm is presented. It can be seen from the figure that the relative illuminance at the maximum field of view is above 40%, with sufficient light input, ensuring that the lens can be used even in a relatively dim environment and there will be no vignetting in the edge field of view of the actual shooting picture.

[0137] Embodiment 2

[0138] Reference Figure 8 and Figure 9 As shown, the optical structure schematic diagram and the optical path structure schematic diagram of this Embodiment 2 are presented respectively. In this embodiment, the field of view angle FOV of the lens = 135°, the lens aperture value F# = 1.6, the total focal length f of the lens optical system = 4.3 mm, the total optical length TTL of the lens = 22.5 mm, the optical back focal length OBFL of the lens = 4.8 mm, and the lens can be maximally matched with a 1 / 1.8-inch chip.

[0139] The lens in this embodiment has the same structure as that in Embodiment 1 along the optical axis of the lens from the object side to the image side, except that: the second lens 2 is an aspherical plastic lens with a negative focal power.

[0140] In this embodiment, the first lens 1 is a spherical glass lens with a negative focal power, its object side is convex, and its image side is concave, that is, it is a meniscus lens with a negative focal power. Its function is to deflect light so that the light enters the optical system; the second lens 2 is an aspherical plastic lens with a negative focal power, its object side is concave, and its image side is convex. Its main function is to adjust the light so that the light enters the optical system smoothly; the third lens 3 is an aspherical plastic lens with a positive focal power, its object side is convex, and its image side is concave. Its function is to correct the spherical aberration of the previous lens and converge the light so that the light fills the pupil; the fourth lens 4 is a biconvex spherical glass lens with a positive focal power, and its Abbe number is greater than 80, which can reduce the defocus shift in the infrared band and improve the resolution in the infrared band; the fifth lens 5 is a biconvex aspherical plastic lens with a positive focal power, and its function is to converge the light and balance the aberration of the front and rear lenses; the sixth lens 6 is an aspherical plastic lens with a negative focal power, its object side is concave, and its image side is concave. Its main function is to diverge the light, expand the imaging surface, and make the system have a larger target surface; the object side of the seventh lens 7 is convex, and its image side is concave. Its main function is to control the incident angle of the chief ray and improve the resolution of the system.

[0141] In this embodiment, the curvature radii (unit: mm), central thickness d (unit: mm), refractive index (ND), Abbe constant (VD), and aspherical K value (Conic) of the first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6, seventh lens 7, eighth lens 8, ninth lens 9, and tenth lens 10 are shown in Table 4.

[0142] Table 4

[0143] Surface number Radius of curvature R Central thickness d Refractive index ND Abbe number VD K 1 200.06 0.85 1.52 64.2 0.00 2 3.58 2.83 0.00 3 -3.78 1.54 1.54 55.7 -0.18 4 -8.71 0.07 -1.11 5 5.53 1.54 1.64 23.9 -2.05 6 6.97 0.59 4.42 7 (diaphragm) Infinity -0.46 0.00 8 6.61 3.89 1.50 81.6 0.00 9 -6.61 0.93 0.00 10 7.88 2.45 1.54 55.7 -1.91 11 -7.32 0.39 -1.02 12 -2.34 0.95 1.64 23.9 -4.73 13 -7.02 0.20 -32.44 14 3.86 1.79 1.54 55.7 -7.09 15 13.67 0.36 -48.25 16 Infinity 0.21 1.52 64.2 0.00 17 Infinity 3.8 0.00

[0144] In Table 4, the surface numbers are numbered according to the surface order of each lens. Among them, "1" represents the front surface of the first lens, "2" represents the rear surface of the first lens, and so on; the curvature radius represents the degree of curvature of the lens surface. A positive value represents that the surface bends towards the image side, and a negative value represents that the surface bends towards the object side. Among them, "Infinity" represents that the surface is a plane; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the current lens material to deflect light, the Abbe number represents the dispersion characteristic of the current lens material to light; the K value represents the numerical value of the best-fit conic coefficient of the aspherical surface.

[0145] The aspheric surfaces of the second lens 2, the third lens 3, the fifth lens 5, the sixth lens 6, and the seventh lens 7 in this embodiment can all be defined by the above equation of the even aspheric surface. Table 5 gives the coefficients of the aspheric surfaces of each optical surface.

[0146] Table 5

[0147] Surface number A B C D E F G 3 1.36E-02 -1.26E-03 1.11E-04 -4.70E-06 -1.84E-07 3.29E-08 -1.12E-09 4 9.10E-03 -8.14E-04 4.92E-05 -2.38E-07 -2.91E-07 2.46E-08 -6.62E-10 5 -2.04E-04 2.12E-04 -6.72E-07 -6.21E-07 -9.35E-09 9.63E-09 -5.23E-10 6 -3.31E-03 5.42E-04 -4.59E-05 -1.85E-06 2.18E-07 5.60E-08 -8.45E-09 10 -7.53E-05 1.01E-07 5.57E-06 1.37E-08 -3.28E-08 1.22E-09 2.51E-10 11 -2.94E-03 -8.23E-05 2.72E-05 -2.52E-07 3.14E-08 -1.70E-08 1.10E-09 12 3.34E-03 -6.93E-04 5.37E-05 -1.80E-06 1.52E-08 6.13E-09 -7.29E-10 13 8.61E-03 -3.50E-04 -1.01E-05 1.93E-06 2.97E-08 -3.08E-09 -2.82E-10 14 -1.61E-03 2.65E-04 -3.44E-05 1.85E-06 -1.22E-08 -5.35E-10 -6.72E-11 15 -1.48E-03 -5.07E-06 -2.27E-06 -1.78E-07 -5.54E-09 2.80E-09 -1.25E-10

[0148] Reference Figure 10 As shown, the MTF curve graphs of different fields of view of the lens in this embodiment at a visible light wavelength of 0.435 - 0.656 μm and a spatial frequency of 200 lp / mm are presented. Among them, the horizontal axis represents the spatial frequency, and the vertical axis represents the MTF value. It can be seen from the figure that when the spatial frequency is 200 lp / mm, the MTF values of the full field of view of the lens are all above 0.3, indicating that this lens has high resolution and can match a higher pixel chip.

[0149] Reference Figure 11 As shown, the MTF curve graph of the lens in this embodiment at an infrared wavelength of 0.85 μm and a spatial frequency of 200 lp / mm is presented. It can be seen from the figure that when the spatial frequency is 200 lp / mm, the MTF values of the full field of view of the lens are all above 0.1, and the MTF value of the central field of view is around 0.3, ensuring that the picture is clear when the lens is used for night shooting and achieving all-weather high-definition monitoring.

[0150] Reference Figure 12 、 Figure 13 As shown, the MTF defocus curve graphs of the lens in this embodiment at a visible light wavelength of 0.435 - 0.656 μm and a spatial frequency of 125 lp / mm at high temperature +70°C and low temperature -30°C are presented respectively. It can be seen from the figure that at high temperature +70°C and low temperature -30°C, the defocus amount is less than or equal to 6 μm, ensuring the resolution of the lens at high temperature +70°C and low temperature -30°C and achieving high-definition picture shooting.

[0151] Reference Figure 14 As shown, the relative illuminance curve graph of the visible light 0.546 μm of the lens in this embodiment is presented. It can be seen from the figure that the relative illuminance at the maximum field of view is above 50%, with sufficient light input, ensuring that the lens can be used even in a relatively dim environment and there will be no vignetting in the edge field of view of the actual shooting picture.

[0152] It can be seen from the MTF curve graphs, defocus curve graphs, and relative illuminance curve graphs of each of the above embodiments that the optical lens provided by the present invention has high resolution, can match a high pixel chip, has the advantages of large target surface imaging, relatively high relative illuminance, and can achieve day and night confocal in high and low temperature environments.

[0153] The above only expresses the preferred technical solutions of the present utility model, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the utility model patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several modifications and improvements can still be made, and the present utility model also intends to include these modifications and deformations.

Claims

1. A large-area, high-pixel, high-resolution security lens, wherein the surface of the lens adjacent to the object plane is defined as the object side surface, and the surface of the lens adjacent to the image plane is defined as the image side surface, and the characteristics are: Set along the lens optical axis from the object side to the image side in order: A first lens, wherein the first lens is a spherical glass lens with negative optical power, the object side surface of which is convex and the image side surface of which is concave; A second lens, the second lens is an aspheric plastic lens having either positive or negative optical power, the object side surface of the second lens being concave and the image side surface being convex; A third lens, the third lens is an aspheric plastic lens with positive refractive power, the object side surface of which is convex, and the image side surface of which is concave; a fourth lens, wherein the fourth lens is a spherical glass lens with positive refractive power, the object side surface of the fourth lens is convex, and the image side surface of the fourth lens is convex; a fifth lens, wherein the fifth lens is an aspheric plastic lens with positive refractive power, 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; a sixth lens, wherein the sixth lens is an aspherical plastic lens with negative optical power, the object side surface of the sixth lens is a concave surface, and the image side surface may be a concave surface; The seventh lens is an aspherical plastic lens with positive refractive power, the object side surface of the seventh lens is convex, and the image side surface may be concave.

2. The large-area, high-pixel, high-resolution security lens according to claim 1, characterized in that: The lens satisfies the following relationship: IC / TTL ≥ 0.39; TTL / f≤5.21; OBFL / TTL ≥ 0.21; In the relationship, f is the total focal length of the optical lens, TTL is the total length of the lens optical system, OBFL is the optical back focus of the lens system, and IC is the total image height of the chip equipped with the lens system.

3. The large-area, high-pixel, high-resolution security lens according to claim 1, characterized in that: The aperture of the lens is F#, satisfying F#≥1.6; The total focal length of the lens is f, satisfying f≥4.3mm; The total length of the lens optical system is TTL, satisfying TTL≤22.5 mm.

4. The large-area, high-pixel, high-resolution security lens according to claim 1, characterized in that: The lens satisfies the following relationship: -1.71≤f1 / f≤-1.42; -3.22≤f2 / f≤32.98; 6.78≤f3 / f≤60.16; 1.39≤f4 / f≤1.7; 1.63≤f5 / f≤2.14; -1.53≤f6 / f≤-1.37; 2.05≤f7 / f≤2.66; In the relationship, f is the total focal length of the optical 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, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.

5. The large-area, high-pixel, high-resolution security lens according to claim 1, characterized in that: The focal length ranges corresponding to the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are respectively -7.62 to -6.81, -147.4 to +166.21, +29.3 to +303.18, +7.0 to +7.34, +7.48 to +10.82, -7.54 to -5.92, and +8.71 to +13.12, and the unit of the focal length is mm.

6. The large-area, high-pixel, high-resolution security lens according to claim 1, characterized in that: The refractive index ranges corresponding to the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are 1.50-1.54, 1.51-1.57, 1.60-1.68, 1.45-1.55, 1.51-1.57, 1.60-1.68 and 1.51-1.57 respectively.

7. The large-area, high-pixel, high-resolution security lens according to claim 1, characterized in that: The object side surface curvature radii corresponding to the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are in the range of +67.8 to +200.06, -3.93 to -3.3, +5.52 to +6.25, +6.37 to +6.61, +7.88 to +16.88, -2.96 to -2.2, and +3.35 to +4.0, respectively; the image side surface curvature radii corresponding to the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are in the range of +3.46 to +3.79, -8.7 to -4.41, +5.05 to +7.51, -6.61 to -6.37, -8.45 to -6.89, -10.86 to -5.93, and +5.62 to +13.68, respectively, and the unit of the curvature radius is mm.

8. The large-area, high-pixel, high-resolution security lens according to claim 1, characterized in that: An aperture plate is also arranged along the optical axis of the lens, and the aperture plate is located between the image side surface of the third lens and the object side surface of the fourth lens.

9. The large-area, high-pixel, high-resolution security lens according to claim 1, characterized in that: Also set along the lens optical axis: A filter, wherein the filter is arranged on the image side of the seventh lens; A protective glass and an image acquisition element, wherein the protective glass is integrated on the image acquisition element, and the image acquisition element is arranged on the image side of the protective glass.

10. The large-image-area, high-pixel, high-resolution security lens according to any one of claims 1 to 9, characterized in that: The aspheric surfaces of the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens can be defined by the following equation for an even-order aspheric surface: Wherein, Z is the vector height of the lens along the optical axis, k is the quadratic cone coefficient, r is the lens height, c is the lens curvature, A, B, C, D, E, F, G are the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order coefficients of the aspheric polynomial.

Images