Large-light-transmission medium-long-focal-length day and night confocal lens and electronic equipment

Abstract

The invention discloses a large-light-transmission medium-long-focal-length day and night confocal lens and electronic equipment. The lens sequentially comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens from an object side to an image side. Wherein the first lens has positive focal power and is provided with an object side surface facing the object side and an image side surface facing the object side, the object side surface is a convex surface, and the image side surface is a concave surface; the range of the ratio of the first lens to the focal length of the lens is 0.961-1.280: 1. The second lens has positive focal power and is provided with an object side surface facing the object side and an image side surface facing the object side, the object side surface is a convex surface, and the image side surface is a concave surface; the range of the ratio of the second lens to the focal length of the lens is 0.719-1.514: 1. According to the invention, through arrangement of the lens and reasonable focal power distribution, the problem of confocal difference of medium and long-focus lenses in day and night use is solved.

Description

Technical Field

[0001] The invention relates to the technical field of medium-long focal length day and night confocal lenses, and in particular to a medium-long focal length day and night confocal lens with large light transmission and electronic equipment. Background Art

[0002] Medium and long focal length lenses are widely used in the field of security monitoring. They not only improve monitoring efficiency, but also enhance the reliability and security of the monitoring system. Existing medium and long focal length lenses have at least one of the following disadvantages:

[0003] 1) Generally, the wavelength range of medium and long focal length lenses is limited to visible light, which cannot meet the needs of night use.

[0004] 2) Generally, medium and long focal length lenses have poor control over transfer functions, resulting in low resolution, low analysis, and uneven images.

[0005] 3) Generally, medium and long focal length lenses have a relatively small light transmission rate. In low-light environments, the incoming light is relatively low and the captured images are relatively dark.

[0006] 4) Generally, medium and long focal length lenses have poor distortion control, which can easily cause deformation of images and objects, resulting in inaccurate recognition.

[0007] 5) Generally, medium and long focal length lenses have obvious blue fringing effect in visible light and poor color reproduction. Summary of the invention

[0008] In view of this, the purpose of the present invention is to provide a large-light medium-long focal length day and night confocal lens and electronic equipment. The lens can solve at least one technical disadvantage mentioned in the background technology.

[0009] According to one aspect of the present invention, a day and night confocal lens with a large light transmission and a medium-long focal length is provided, which comprises a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in order from the object side to the image side; wherein the first lens has a positive optical power, has an object side surface facing the object side and an image side surface facing the object side, the object side surface is a convex surface, and the image side surface is a concave surface; the ratio of the first lens to the focal length of the lens is in the range of 0.961 to 1.280:1; The second lens has positive refractive power, has an object side surface facing the object side and an image side surface facing the object side, the object side surface is convex, and the image side surface is concave; the ratio range of the second lens to the focal length of the lens is: 0.719 to 1.514:1; the third lens has negative refractive power, has an object side surface facing the image side and an image side surface facing the object side, the object side surface is convex, and the image side surface is concave; the ratio range of the third lens to the focal length of the lens is: -0.716 to -0.348:1; The fourth lens has negative power, has an object side surface facing the object side and an image side surface facing the image side, the object side surface is concave, and the image side surface is concave; the ratio range of the fourth lens to the focal length of the lens is: -0.250 to -0.307:1; the fifth lens has positive power, has an object side surface facing the object side and an object side surface facing the object side, the object side surface is convex, and the image side surface is convex; the ratio range of the fifth lens to the focal length of the lens is: 0.250 to 0.328:1; The sixth lens has negative power, has an object side surface facing the object side and an image side surface facing the image side, the object side surface is convex, and the image side surface is convex; the ratio range of the sixth lens to the focal length of the lens is: -1.427 to -0.718:1; the seventh lens has positive power, has an object side surface facing the object side and an image side surface facing the object side, the object side surface is convex, and the image side surface is convex; the ratio range of the seventh lens to the focal length of the lens is: 0.587 to 0.644:1;

[0010] In the above technical solution, the problem of confocal difference between medium and long focal length lenses in day and night use is solved by setting the lens and reasonably distributing the focal length. In the design stage, the present invention achieves a high resolution of eight million pixels for a 1 / 1.8-inch imaging sensor, and maintains an excellent resolution of 200lp / mm@0.3 in the entire field of view. The medium and long focal length lens of the present invention covers the visible light wavelength range of 435-650nm and the night vision wavelength of 850nm. It adopts a confocal design and can be used day and night without adjusting the focal length. In addition, the lens is composed of only 7 optical lenses, the total optical length is controlled within 22mm, it is compatible with the M12 threaded interface, and an extremely compact optical structure is adopted inside. The overall design meets the requirements of lightweight design while ensuring the volume and weight. When the ratio meets the above relationship, the light will have a flatter angle, reduce the tolerance sensitivity and improve the yield stability of the optical lens. The more even sharing of the focal length of each lens is also conducive to the miniaturization of the optical lens. The lens of the present invention has a large aperture of F2, which can capture sufficient light even in a low-light environment to ensure the clarity of the monitoring screen. Thanks to the advantage of the large aperture, the lens provides excellent depth of field control when shooting, and can produce a good blur effect in the background, thereby highlighting the monitoring target. The focal length is set to 16.3mm, which is suitable for long-distance monitoring. It not only ensures a wide viewing angle, but also has a certain telephoto capability, and can capture clear images at a longer distance, which is crucial for long-distance monitoring scenes. Furthermore, the lens of the present invention performs well in ghost image control, with small ghost image energy, and small pixels and target surface areas occupied. By reasonably selecting lens materials and accurately allocating positive and negative values ​​of optical focal length, the present invention effectively balances the low-order aberrations of the lens, reduces sensitivity to manufacturing tolerances, improves the resolving power and resolution performance of the optical system, and achieves excellent optical performance even under existing manufacturing conditions.

[0011] In some embodiments, the first lens is a positive meniscus lens made of a high refractive index material; and the sixth lens is a negative meniscus lens.

[0012] In the above technical solution, the first lens adopts a meniscus design, and the use of high refractive index materials ensures that the optical system can effectively compress the front aperture of the optical system while maintaining a large field of view, a large angle and a large aperture ratio. This design not only helps to achieve the miniaturization of the lens, but also provides support for distortion-free optical performance. The sixth lens is a meniscus negative lens that can effectively diverge light, thereby increasing the image size and reducing the angle at which the main light of the lens enters the sensor. This design not only optimizes the imaging quality, but also helps to further improve the overall performance of the optical system.

[0013] In some embodiments, the lens satisfies the following condition:

[0014] Nd 2 <1.6; Vd 2 >68

[0015] Nd 3 >1.7; Vd 3 <30

[0016] Where Nd 2 is the refractive index of the second lens; Vd 2 is the Abbe coefficient of the second lens; Nd 3 is the refractive index of the third lens; Vd 3 is the Abbe coefficient of the third lens.

[0017] In the above technical solution, the combination of high and low dispersion materials is conducive to correcting secondary chromatic aberration and can effectively improve the imaging quality. Axial chromatic aberration can be corrected by two lenses, the second and third lenses. The second lens with a positive focal length has a lower dispersion, that is, a higher Abbe number, and the third lens with a negative focal length has a higher dispersion, that is, a lower Abbe number. This lens group can correct primary chromatic aberration so that the cut-off long-wavelength red light and the short-wavelength blue light coincide with each other on the optical axis. This effective correction of chromatic aberration can bring advantages such as small blue-purple edge of the imaging lens and clear optical imaging performance.

[0018] In some embodiments, the lens satisfies the following condition:

[0019] 1.55 <Nd 4 <1.65; Vd 4 <41

[0020] 1.55 <Nd 5 <1.65; Vd 5 <69

[0021] Where Nd 4 is the refractive index of the fourth lens; Vd 4 is the Abbe coefficient of the fourth lens; Nd 5 Vd is the refractive index of the fifth lens; 5 is the Abbe coefficient of the fifth lens.

[0022] In the above technical solution, axial chromatic aberration can be corrected by two lenses, the fourth and fifth lenses. The fifth lens with positive focal length has lower dispersion, i.e., higher Abbe number, and the fourth lens with negative focal length has higher dispersion, i.e., lower Abbe number. This lens group can correct primary chromatic aberration so that the focus of the cut-off long-wavelength red light and the short-wavelength blue light on the optical axis coincide. This effective correction of chromatic aberration can bring advantages such as small blue-purple edge of the imaging lens and clear optical imaging performance.

[0023] In some embodiments, the refractive index temperature coefficient dn / dT of the material of the second lens and the fifth lens is less than -6*10E-6 in the temperature range of -40°C to 105°C.

[0024] In the above technical solution, the use of materials with special refractive index temperature coefficients can effectively balance temperature drift and achieve athermalization. The second and fifth lenses with positive focal lengths use materials with negative refractive index temperature coefficients, which can effectively reduce the imaging surface offset caused by thermal expansion and contraction of lens structural parts, so that the lens does not need additional focusing at different temperatures, and the imaging performance of the imaging lens at different temperatures is clear and consistent, so as to balance temperature drift and achieve the purpose of athermalization of the lens.

[0025] In some embodiments, the second lens and the third lens are glued together to form a first glued lens group; the fourth lens and the fifth lens are glued together to form a second glued lens group; and the aperture is disposed between the first glued lens group and the second glued lens group.

[0026] In the above technical solution, the second lens is a meniscus positive lens, and the third lens is a meniscus negative lens, which together form the first cemented lens group on the object side with negative focal length. This combination works in synergy with the first lens, is responsible for the imaging range of the wide-angle field of view, and effectively compensates for the aberrations generated by the first lens under a large field of view. In addition, the combination reduces the impact of the off-axis field of view light on the sensing element by suppressing the incident angle of the light of the edge field of view on the subsequent optical element, so that the incident angle of the light of the edge field of view on the subsequent optical element is small, thereby further correcting the aberration of the off-axis field of view and improving the resolution of the optical system. The fourth lens is a biconcave negative lens, and the fifth lens is a biconvex positive lens, forming the second cemented lens group on the object side with positive focal length. This combination effectively converges the angle of light entering the aperture and the rear group through the design of the cemented lens, reducing the sensitivity of the large-aperture wide-angle optical lens to the angle. At the same time, the combination plays a key role in correcting the spherical aberration and coma under a large field of view, and further balances the aberrations generated by the front lens of the lens. The second and fifth lenses with positive focal lengths have lower dispersion, i.e., higher Abbe numbers, while the third and fourth lenses with negative focal lengths have higher dispersion, i.e., lower Abbe numbers. The first cemented lens group C1 and the second cemented lens group C2 in this combination are responsible for correcting primary chromatic aberration, so that the cut-off long-wavelength red light and the short-wavelength blue light coincide with each other at their focal points on the optical axis. In the layout of the optical system, an aperture is set between the first cemented lens group and the second cemented lens group to form a double Gauss lens structure. In this structure, the positive distortion characteristics of the front group are fully utilized to overcome the traditional limitations of double Gauss lenses in terms of small light transmission and large distortion. This design not only optimizes the efficiency of light entering the aperture, but also significantly improves the overall performance of the optical system.

[0027] In some embodiments, the fourth lens and the fifth lens are cemented together to form a second cemented lens group; the lens satisfies the following conditional formula:

[0028] Vd 2 -Vd 3 >33

[0029] Where Vd 2 is the Abbe coefficient of the second lens, Vd 3 is the Abbe coefficient of the third lens.

[0030] In the above technical solution, the second lens is a positive meniscus lens, and the third lens is a negative meniscus lens, which together constitute a first cemented lens group on the object side with negative optical power. This combination works in synergy with the first lens, is responsible for the imaging range of the wide-angle field of view, and effectively compensates for the aberrations generated by the first lens at a large field of view. In addition, the combination reduces the impact of off-axis field of view light on the sensing element by suppressing the incident angle of the light in the edge field of view, so that the incident angle of the light in the edge field of view on the subsequent optical element is small, thereby further correcting the aberration of the off-axis field of view and improving the resolution of the optical system. At the same time, the combination of high and low dispersion materials is conducive to correcting secondary chromatic aberrations and can effectively improve the imaging quality.

[0031] In some embodiments, the fourth lens and the fifth lens are glued together to form a second glued lens group, or the fourth lens, the fifth lens and the sixth lens are glued together to form a second glued lens group; the lens satisfies the following conditional formula:

[0032] Vd 5 -Vd 4 >27

[0033] Where Vd 4 is the Abbe coefficient of the fourth lens, Vd 5 is the Abbe coefficient of the fifth lens.

[0034] In the above technical solution, the fourth lens is a biconcave negative lens, and the fifth lens is a biconvex positive lens, forming a second cemented lens group on the object side with positive focal power. This combination effectively converges the angle of light entering the aperture and the rear group through the design of the cemented lens, reducing the sensitivity of the large aperture wide-angle optical lens to the angle. At the same time, this combination plays a key role in correcting spherical aberration and coma under a large field of view, and further balances the aberration generated by the front lens of the lens. The combination of high and low dispersion materials is conducive to correcting secondary chromatic aberration and can effectively improve the imaging quality. The fourth, fifth, and sixth lenses form the second lens group, and are three cemented lenses. The advantage is that chromatic aberration is eliminated by using the curvature radius values, thicknesses and different optical materials of three different components to eliminate chromatic aberration, so that the cut-off long-wavelength red light and the short-wavelength blue light overlap at the focus on the optical axis, reducing the blue-purple edge phenomenon of the imaging.

[0035] In some embodiments, the lens satisfies the following condition:

[0036] ∣R 11 -R 10 ∣>5

[0037] Nd 7 >1.85

[0038] In the formula, R 10 is the radius of curvature of the sixth lens on the object side, R 11 Nd is the curvature radius of the sixth lens image side; 7 is the refractive index of the seventh lens.

[0039] In the above technical solution, in the field of optical design, the performance of the lens is affected by many factors. For concentric lenses, the yield of their optical properties is low during the cold processing and grinding stage, and the eccentricity accuracy is difficult to guarantee, which is mainly affected by the geometric shape and manufacturing tolerance of the lens. In order to overcome these limitations, this case sets |R 11 -R 10 ∣>5. The design of the seventh lens adopts a material with a high refractive index. This strategy not only optimizes the optical performance of the lens and improves the imaging resolution, but also effectively reduces the outer diameter of the rear end of the lens. Through this design, the lens meets the specification requirements of the M12 threaded interface, thereby enhancing its versatility in application in a variety of imaging systems. The application of high refractive index materials enables the lens to achieve a more compact size design while maintaining high optical performance, which is of great significance for improving the integration and portability of the system. In addition, the compatibility of the M12 threaded interface enables the lens to be easily adapted to a variety of standard cameras and imaging devices, thereby broadening its scope of application in different optical systems.

[0040] According to another aspect of the present invention, there is provided an electronic device, comprising: a high-clearance medium-long focal length day and night confocal lens according to the above-mentioned high-clearance medium-long focal length day and night confocal lens; and an image sensor configured to receive an image formed by the high-clearance medium-long focal length day and night confocal lens.

[0041] In the above technical solution, the advantages of the electronic device rely on the large-light medium-long focal length day and night confocal lens, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 these drawings without paying creative work.

[0043] Figure 1 This is a structural schematic diagram of Example 1 of a large-light-through medium-long focal length day-night confocal lens of the present invention;

[0044] Figure 2 This is the MTF diagram of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0045] Figure 3 This is the MTF diagram of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention at 850nm at night;

[0046] Figure 4 This is a TFM diagram of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0047] Figure 5 This is a TFM diagram of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0048] Figure 6 It is a field curvature and distortion diagram of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0049] Figure 7 This is a light fan diagram of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0050] Figure 8 This is a vertical axis chromatic aberration diagram of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0051] Fig. 9 This is a relative illumination diagram of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435nm-650nm;

[0052] Fig.10 This is a graph showing the variation of the maximum principal ray incident angle with the normalized image plane of Example 1 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0053] Fig.11 This is a structural schematic diagram of Example 2 of a large-clearance, medium-long focal length day-night confocal lens of the present invention;

[0054] Fig.12This is the MTF diagram of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0055] Fig.13 This is the MTF diagram of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention at 850nm at night;

[0056] Fig.14 This is a TFM diagram of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0057] Fig.15 This is a TFM diagram of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0058] Fig.16 It is a field curvature and distortion diagram of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0059] Fig.17 This is a light fan diagram of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0060] Fig.18 This is a vertical axis chromatic aberration diagram of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0061] Fig.19 This is a relative illumination diagram of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435nm-650nm;

[0062] Fig. 20 This is a graph showing the variation of the maximum principal ray incident angle with the normalized image plane of Example 2 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0063] Fig.21 This is a structural schematic diagram of Example 3 of a large-light-through medium-long focal length day-night confocal lens of the present invention;

[0064] Fig. 22 This is the MTF diagram of Example 3 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0065] Fig.23 This is the MTF diagram of Example 3 of a large-clearance medium-long focal length day-night confocal lens of the present invention at 850nm at night;

[0066] Fig.24 This is a TFM diagram of Example 3 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0067] Fig.25This is a TFM diagram of Example 3 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0068] Fig.26 It is a field curvature and distortion diagram of Example 3 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0069] Fig. 27 This is a light fan diagram of Example 3 of a large-light medium-long focal length day-night confocal lens of the present invention;

[0070] Fig.28 This is a vertical axis chromatic aberration diagram of Example 3 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0071] Fig.29 This is a relative illumination diagram of Example 3 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435nm-650nm;

[0072] Fig.30 This is a graph showing the variation of the maximum principal ray incident angle with the normalized image plane of Example 3 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0073] Fig.31 This is a structural schematic diagram of Example 4 of a large-light-through medium-long focal length day-night confocal lens of the present invention;

[0074] Fig.32 This is the MTF diagram of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0075] Fig.33 This is an MTF diagram of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention at 850nm at night;

[0076] Fig.34 This is a TFM diagram of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0077] Fig.35 This is a TFM diagram of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435-650nm;

[0078] Fig.36 It is a field curvature and distortion diagram of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0079] Fig.37 This is a light fan diagram of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0080] Fig.38 This is a vertical axis chromatic aberration diagram of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention;

[0081] Fig.39 This is a relative illumination diagram of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention under visible light 435nm-650nm;

[0082] Fig.40 This is a graph showing the variation of the maximum principal ray incident angle with the normalized image plane of Example 4 of a large-clearance medium-long focal length day-night confocal lens of the present invention; Fig.41 This is a schematic diagram of the structure of an electronic device example 5 of the present invention. DETAILED DESCRIPTION

[0083] The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention. Similarly, the following examples are only partial embodiments of the present invention rather than all embodiments, and all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0084] The object of the present invention is to provide a day and night confocal lens and electronic equipment with high optical performance and large light transmission, medium and long focal length. An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Figure 1 , Fig.11 , Fig.21 , Fig.31 They are cross-sectional views of the high-throughput, medium-long focal length day and night confocal lenses (optical systems) according to Examples 1 to 4, respectively. The high-throughput, medium-long focal length day and night confocal lenses according to each example are used for electronic devices including imaging devices such as digital cameras, digital still cameras, broadcast cameras, surveillance cameras, and interchangeable lenses. In each cross-sectional view, the left side is the object side OBJ and the right side is the image side IMA. In each cross-sectional view, Li represents the i-th lens, and Ci represents the i-th group of cemented lenses. ST represents an aperture (fixed aperture or visible aperture), OA represents the optical axis, G1 is a filter, and G2 is a protective sheet. IMA represents an image plane, and when the high-throughput, medium-long focal length day and night confocal lenses 1 to 4 according to each example are used in the imaging optical system of a digital camera or a digital still camera, a solid-state imaging element (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor is arranged on the imaging plane IMA.

[0085] According to various examples, the day-night confocal lens with a large clear light and a medium-long focal length includes, in order from the object side to the image side: a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7; wherein the first lens L1 has positive refractive power, has an object side surface facing the object side and an image side surface facing the object side, the object side surface is a convex surface, and the image side surface is a concave surface; the ratio range of the first lens to the focal length of the lens is: 0 .961~1.280:1; the second lens L2 has positive refractive power, has an object side surface facing the object side and an image side surface facing the object side, the object side surface is convex, and the image side surface is concave; the ratio range of the second lens to the focal length of the lens is: 0.719~1.514:1; the third lens L3 has negative refractive power, has an object side surface facing the image side and an image side surface facing the object side, the object side surface is convex, and the image side surface is concave; the ratio range of the third lens to the focal length of the lens is:

[0086] The fourth lens L4 has a negative optical power, has an object side surface facing the object side and an image side surface facing the image side, the object side surface is concave, and the image side surface is concave; the ratio range of the fourth lens to the focal length of the lens is: -0.250 to -0.307:1; the fifth lens L5 has a positive optical power, has an object side surface facing the object side and an object side surface facing the object side, the object side surface is convex, and the image side surface is convex; the ratio range of the fifth lens to the focal length of the lens is: 0.250 to 0.328:1; the sixth lens L6 has a negative optical power, has an object side surface facing the object side and an object side surface facing the object side, the object side surface is convex, and the image side surface is convex; The image side surface faces the image side, the object side surface is convex, and the image side surface is convex; the ratio range of the sixth lens to the focal length of the lens is: -1.427 to -0.718:1; the seventh lens L7 has positive focal power, has an object side surface facing the object side and an image side surface facing the object side, the object side surface is convex, and the image side surface is convex; the ratio range of the seventh lens to the focal length of the lens is: 0.587-0.644:1; when the ratio satisfies the above relationship, the light will have a flatter angle, reduce tolerance sensitivity and improve the yield stability of the optical lens, and each lens shares the focal power more evenly, which is also conducive to the miniaturization of the optical lens.

[0087] In this embodiment, the first lens is a meniscus positive lens made of a high refractive index material; the sixth lens is a meniscus negative lens; and the seventh lens is a plano-convex positive lens.

[0088] The high-throughput medium-long focal length day-night confocal lens according to each example may satisfy at least one of the following setting conditions 1) to 7):

[0089] 1)Nd 2 <1.6; Vd 2 >68; Nd 3 >1.7; Vd3 <30;

[0090] 2)1.55 <Nd 4 <1.65; Vd 4 <41;1.55 <Nd 5 <1.65; Vd 5 <69;

[0091] 3) The refractive index temperature coefficient dn / dT of the material of the second lens and the fifth lens is less than -6*10E-6 in the temperature range of -40°C to 105°C;

[0092] 4) Vd 2 -Vd 3 >33;

[0093] 5) Vd 5 -Vd 4 >27;

[0094] 6) | R 11 -R 10 ∣>5;

[0095] 7)Nd 7 >1.85;

[0096] In the above conditional formula, Nd 2 is the refractive index of the second lens; Vd 2 is the Abbe coefficient of the second lens; Nd 3 is the refractive index of the third lens; Vd 3 is the Abbe coefficient of the third lens; Nd 4 is the refractive index of the fourth lens; Vd 4 is the Abbe coefficient of the fourth lens; Nd 5 Vd is the refractive index of the fifth lens; 5 is the Abbe coefficient of the fifth lens; R 10 is the radius of curvature of the sixth lens on the object side, R 11 Nd is the curvature radius of the sixth lens image side; 7 is the refractive index of the seventh lens.

[0097] Conditional formula 1) defines the refractive index and Abbe number of the second lens and the third lens. By setting the conditions appropriately, the two lenses are made of high and low dispersion materials, which is conducive to correcting the secondary chromatic aberration and can effectively improve the imaging quality. Among them, in the above settings: if the refractive index of the second lens is higher than the upper limit, it will make it difficult to compensate for the spherical aberration formed by the first lens; if the Abbe number of the second lens is lower than the lower limit, it will be unfavorable to correct the axial chromatic aberration and magnification chromatic aberration of the lens; if the refractive index of the third lens is lower than the lower limit, it will lead to uneven distribution of optical power and reduced tolerance, resulting in low yield; if the Abbe number of the third lens is higher than the upper limit, it will be unfavorable to correct the axial chromatic aberration and magnification chromatic aberration of the lens; in addition, in order to reliably obtain the effect of conditional formula 1), it is more preferred to set the value of conditional formula 1) to Nd 2 =1.59;

[0098] Vd 2 =38.34; Nd 3 =1.72.;Vd 3 =28.32

[0099] Conditional formula 2) defines the refractive index and Abbe number of the fourth lens and the fifth lens. By setting the conditions appropriately, the achromatic effect (the cut-off long-wavelength red light and the short-wavelength blue light coincide with each other on the optical axis) is achieved. Among them, in the above settings: if the refractive index of the fourth lens is lower than the lower limit or higher than the upper limit, it will lead to uneven distribution of optical power and reduced tolerance, resulting in low yield; if the refractive index of the fifth lens is lower than the lower limit or higher than the upper limit, it will lead to poor temperature drift. If the Abbe number of the fourth lens is higher than the upper limit, it will lead to weak optical aberration compensation balance ability before the aperture, and the light cannot enter the image plane at a gentle angle. If the Abbe number of the fifth lens is higher than the upper limit, it will lead to axial chromatic aberration and magnification chromatic aberration that are not conducive to correcting the lens. In addition, in order to reliably obtain the effect of conditional formula 2), it is more preferred to set the value of conditional formula 2) to Nd4=1.60; Vd4=38; Nd5<1.65; Vd5=68.34.

[0100] Conditional formula 3) defines the temperature coefficients of the second lens and the fifth lens. By setting appropriate conditions and using materials with special refractive index temperature coefficients, the temperature drift can be effectively balanced and athermalization can be achieved. In addition, in order to reliably obtain the effect of conditional formula 2), the material part can be selected from H-ZPK5, H-ZPK7, FCD515, and FCD1.

[0101] Conditional formula 4) defines the difference in Abbe numbers between the second lens and the third lens in the first cemented lens group. By setting the conditions appropriately, the combination of high and low dispersion materials is conducive to correcting secondary chromatic aberration and can effectively improve the image quality. Among them, in the above setting: if it is lower than the lower limit value, it will lead to insufficient correction of the axial chromatic aberration and magnification chromatic aberration of the lens. In addition, in order to reliably obtain the effect of conditional formula 4), it is more preferable to set the value of conditional formula 4) to Vd2-Vd3=40.

[0102] The conditional formula 5) defines the difference in the Abbe number of the fifth lens and the fourth lens in the second cemented lens group. By setting the conditions appropriately, the combination of high and low dispersion materials is conducive to correcting the secondary chromatic aberration and can effectively improve the image quality. Among them, in the above setting: if it is lower than the lower limit value, it will lead to insufficient correction of the axial chromatic aberration and magnification chromatic aberration of the lens. In addition, in order to reliably obtain the effect of the conditional formula 5), ​​it is more preferable to set the value of the conditional formula 5) to Vd5-Vd4=30.

[0103] The conditional formula 6) defines the curvature radius of the front and rear surfaces of the sixth lens. By setting the conditions appropriately, the problem of low yield and difficult to ensure eccentricity accuracy of the concentric lens during the cold working and grinding stage can be solved. In addition, in order to reliably obtain the effect of the conditional formula 6), it is more preferred to set the value of the conditional formula 6) to |R11-R10|

[0104] =5.5,.

[0105] The conditional formula 7) defines the refractive index of the seventh lens. By setting the condition appropriately, the design of the seventh lens adopts a material with a high refractive index. This strategy not only optimizes the optical performance of the lens and improves the imaging resolution, but also effectively reduces the outer diameter of the rear end of the lens. In addition, in order to reliably obtain the effect of the conditional formula 7), it is more preferred to set the value of the conditional formula 7) to 1.75, and more preferably to 1.90.

[0106] A detailed description will now be given of a large-clearance, medium-long focal length day-night confocal lens according to various examples.

[0107] Example 1

[0108] For the optical structure of Example 1, please refer to Figure 1, the specific parameters of Example 1 are shown in Table 1 below. In Example 1, lens F#=2, lens focal length f=16.3mm, diagonal field of view angle FOV=30.80, total length TTL=22.00; optical back focus BFL=8.20; lens design image height h=8.86; TTL / h=2.48 (the parameters indicate that the scheme of the present invention can realize the miniaturization of the optical lens, and the total length is shorter under the same imaging range); (FOV*f) / h=56.66 (the parameters indicate that the scheme of the present invention can achieve high angular resolution and a wider field of view at different focal lengths). The second lens L2 and the third lens L3 are glued to form a first glued lens group C1; the fourth lens L4 and the fifth lens L5 are glued to form a second glued lens group C2; the aperture ST is arranged between the first glued lens group C1 and the second glued lens group C2. Conditional equations 1) to 7) are as follows: 1) 1Nd 2 =1.59; Vd 2 =68.34; Nd 3 =1.73; Vd 3 =28.32; 2)Nd 4 =1.61; Vd 4 =37; Nd 5 =1.59; Vd 5 =68.34; 3) The refractive index temperature coefficient of the material of the second lens and the fifth lens is dn / dT<-6*10E-6 in the temperature range of -40°C to 105°C; 4) Vd 2 -Vd 3 =40.02; 5) Vd 5 -Vd 4 =31.34; 6)|R 11 -R 10 ∣>5;7)Nd 7 =1.91;

[0109] Table 1 Example 1 Parameters

[0110]

[0111]

[0112] See also Figure 2 , Example 1 lens MTF diagram under visible light 435-650nm, when the field of view angle FOV = 30.8°, the target surface size IMH = 8.86mm, the MTF value is greater than 0.4 at 160lp / mm, indicating that this example has high resolution and good imaging quality. Please refer to Figure 3, Example 1 lens MTF diagram at night at 850nm, when the field of view angle FOV = 30.8°, the target surface size IMH = 8.86mm, the MTF value is greater than 0.2 at 160lp / mm, indicating that this example has high resolution and good imaging quality at night (850nm). Please refer to Figure 4 , Example 1 lens TFM diagram under visible light 435-650nm, field of view FOV = 30.8°, target surface size IMH = 8.86mmMTF frequency at 73lp / mm focal depth> 40um, indicating that this example lens has good aberration and large focal depth. Please refer to Figure 5 , Example 1 TFM diagram of the lens at night at 850nm, at the field of view angle FOV = 30.82°, the target surface size IMH = 8.86mmMTF frequency is 73lp / mm, and the defocus of the visible and infrared center field of view of the lower lens is <7um. Please refer to Figure 6 , Example 1 lens field curvature and distortion diagram,, According to the image display, the field curvature curve of this example at 435-650 wavelength shows that both T-line and S-line have good convergence, field curvature and astigmatism are very good, ensuring the uniform imaging of the entire image, distortion <2% in absolute value symbol, the lens is close to distortion-free lens, please refer to Figure 7 , the ray fan diagram of the lens of Example 1 shows that the chromatic aberration and coma of the 435-650 wavelength are well corrected, meeting the pixel requirements. Figure 8 , the vertical axis chromatic aberration diagram of the lens in Example 1 shows that the magnification chromatic aberration and coma at wavelengths of 435-650 are well corrected, meeting the pixel requirements. Fig. 9 , Example 1 lens relative illumination diagram under visible light 435nm-650nm, it can be seen that the relative illumination of the lens is greater than 60% when the target surface size IMH=8.86mm. Please refer to Fig.10 , Example 1 The maximum principal ray incident angle of the lens changes with the normalized image plane. It can be seen that the maximum principal ray incident angle of the lens is 13.5° when the target surface size IMH=8.86mm.

[0113] Example 2

[0114] For the optical structure of Example 2, please refer to Fig.11, the specific parameters of Example 2 are shown in Table 2 below. In Example 2, lens F#=2, lens focal length f=16.3mm, diagonal field of view angle FOV=30.80, total length TTL=22.00; optical back focus BFL=7.7; lens design image height h=8.86; TTL / h=2.48 (this parameter indicates that the solution of the present invention can achieve the miniaturization of the optical lens, and the total length is shorter under the same imaging range); (FOV*f) / h=56.66 (this parameter indicates that the solution of the present invention can achieve high angular resolution and a wider field of view at different focal lengths). In addition, the second lens and the third lens do not adopt a cemented lens solution. The fourth lens L4 and the fifth lens L5 are cemented to form a first cemented lens group C1; the aperture ST is arranged between the third lens L3 and the second cemented lens group C1. Conditional equations 1) to 7) are as follows: 1) Nd 2 =1.59; Vd 2 =68.34; Nd 3 =1.72; Vd 3 =34.76; 2)Nd 4 =1.58; Vd 4 =40.75; Nd 5 =1.59; Vd 5 =68.34; 3) The refractive index temperature coefficient of the material of the second lens and the fifth lens is dn / dT<-6*10E-6 in the temperature range of -40°C to 105°C; 4) Vd 2 -Vd 3 =33.58; 5) Vd 5 -Vd 4 =27.59;6)|R 11 -R 10 ∣>5;7)Nd 7 =1.95;

[0115] Table 2 Example 2 Parameters

[0116]

[0117]

[0118] See also Fig.12 The MTF diagram of the lens in Example 2 under visible light 435-650nm shows that the MTF value is greater than 0.3 at 160lp / mm when the field of view angle FOV = 30.82° and the target surface size IMH = 8.86mm, indicating that this example has high resolution and good imaging quality. Fig.13, Example 2 lens MTF diagram at night at 850nm, when the field of view angle FOV = 30.82°, the target surface size IMH = 8.86mm, the MTF value is greater than 0.12 at 160lp / mm, indicating that this example has high resolution and good imaging quality at night (850nm). Please refer to Fig.14 , Example 2 lens TFM diagram under visible light 435-650nm, field of view FOV = 30.82°, target surface size IMH = 8.86mmMTF frequency at 73lp / mm focal depth> 40um, indicating that this example lens has good aberration and large focal depth. Please refer to Fig.15 , Example 2 TFM diagram of the lens at night at 850nm, at the field of view angle FOV = 30.82°, the target surface size IMH = 8.86mmMTF frequency is 73lp / mm, and the defocus of the visible and infrared center field of view of the lower lens is <10um. Please refer to Fig.16 , Example 2 lens field curvature and distortion diagram, the field curvature curve at 435-650 wavelength in this example shows that both T line and S line have good convergence, field curvature and astigmatism are very good, ensuring the uniform imaging of the entire image, distortion <2% in absolute value symbol, the lens is close to distortion-free lens. Please refer to Fig.17 , Light fan diagram of lens in Example 2, this embodiment has a good correction for magnification chromatic aberration and coma at wavelengths of 435-650, meeting the pixel requirements. Fig.18 , the vertical axis chromatic aberration diagram of the lens in Example 2 shows that the magnification chromatic aberration and coma at wavelengths of 435-650 are well corrected, meeting the pixel requirements. Fig.19 , Example 2 lens relative illumination diagram under visible light 435nm-650nm, it can be seen that the relative illumination of the lens is greater than 60% when the target surface size IMH=8.86mm. Please refer to Fig. 20 , Example 2 The maximum principal ray incident angle of the lens changes with the normalized image plane. It can be seen that the maximum principal ray incident angle of the lens is 13° when the target surface size IMH=8.86mm.

[0119] Example 3

[0120] For the optical structure of Example 3, please refer to Fig.21, the specific parameters of Example 3 are shown in Table 3 below. In Example 3, lens F#=2, lens focal length f=16.3mm, diagonal field of view angle FOV=30.56, total length TTL=22.00; optical back focus BFL=7.24; lens design image height h=8.86; TTL / h=2.48 (the parameters indicate that the scheme of the present invention can realize the miniaturization of the optical lens, and the total length is shorter under the same imaging range); (FOV*f) / h=56.21 (the parameters indicate that the scheme of the present invention can achieve high angular resolution and a wider field of view at different focal lengths). The second lens L2 and the third lens L3 are glued to form a first glued lens group C1; the fourth lens L4 and the fifth lens L5 are glued to form a second glued lens group C2; the aperture ST is arranged between the first glued lens group C1 and the second glued lens group C2. Conditional equations 1) to 7) are as follows: 1) Nd 2 =1.59; Vd 2 =68.34; Nd 3 =1.74; Vd 3 =27.77; 2)Nd 4 =1.62; Vd 4 =36.33; Nd 5 =1.59; Vd 5 =68.34; 3) The refractive index temperature coefficient of the material of the second lens and the fifth lens is dn / dT<-6*10E-6 in the temperature range of -40°C to 105°C; 4) Vd 2 -Vd 3 =40.57; 5) Vd 5 -Vd 4 =32.04; 6)|R 11 -R 10 ∣>5;7)Nd 7 =1.95;

[0121] Table 3 Example 3 Parameters

[0122]

[0123] See also Fig. 22 The MTF diagram of the lens in Example 3 under visible light 435-650nm shows that the MTF value is greater than 0.3 at 160lp / mm when the field of view angle FOV = 30.82° and the target surface size IMH = 8.86mm, indicating that this example has high resolution and good imaging quality. Fig.23 The MTF diagram of the lens in Example 3 at night at 850nm shows that the MTF value at 160lp / mm is greater than 0.2 when the field of view angle FOV = 30.82° and the target surface size IMH = 8.86mm, indicating that this example has high resolution and good imaging quality at night (850nm). Fig.24 , Example 3 lens TFM diagram under visible light 435-650nm, field of view angle FOV = 30.82°, target surface size IMH = 8.86mmMTF frequency at 73lp / mm focal depth> 35um, indicating that this example lens has good aberration and large focal depth. Please refer to Fig.25 , Example 3 lens TFM diagram at night at 850nm, field of view angle FOV = 30.82°, target surface size IMH = 8.86mmMTF frequency is 73lp / mm, the lower lens visible and infrared center field of view defocus <6um. Please refer to Fig.26 , Example 3 lens field curvature and distortion diagram, the field curvature curve at 435-650 wavelength in this example shows that both T line and S line have good convergence, field curvature and astigmatism are very good, ensuring the uniform imaging of the entire image, distortion < 2% in absolute value, the lens is close to distortion-free lens. Please refer to Fig. 27 , Light fan diagram of the lens in Example 3. This example has good correction for magnification chromatic aberration and coma at wavelengths of 435-650, meeting the pixel requirements. Fig.28 , the vertical axis chromatic aberration diagram of the lens in Example 3 shows that the magnification chromatic aberration and coma at wavelengths of 435-650 are well corrected, meeting the pixel requirements. Fig.29 , Example 3 lens relative illumination diagram under visible light 435nm-650nm, it can be seen that the relative illumination of the lens is greater than 60% when the target surface size IMH=8.86mm. Please refer to Fig.30 , Example 3 lens maximum principal ray incident angle changes with the normalized image plane. It can be seen that the maximum principal ray incident angle of the lens is 13° when the target surface size IMH=8.86mm.

[0124] Example 4

[0125] For the optical structure of Example 4, please refer to Fig.31, the specific parameters of Example 4 are shown in Table 4 below. In Example 4, lens F#=2, lens focal length f=16.3mm, diagonal field of view angle FOV=31.09, total length TTL=22.00; optical back focus BFL=8; lens design image height h=8.86; TTL / h=2.48 (the parameters indicate that the scheme of the present invention can realize the miniaturization of the optical lens, and the total length is shorter under the same imaging range); (FOV*f) / h=57.19 (the parameters indicate that the scheme of the present invention can realize high angular resolution and a wider field of view at different focal lengths). The second lens L2 and the third lens L3 are glued to form a first glued lens group C1; the fourth lens L4, the fifth lens L5 and the sixth lens L6 are glued to form a second glued lens group C2; the aperture ST is arranged between the first glued lens group C1 and the second glued lens group C2. The advantage of this arrangement is that chromatic aberration is eliminated by using three different components with different radius of curvature, thickness and different optical materials, so that the focus of the cut-off long-wavelength red light and the short-wavelength blue light on the optical axis coincides, reducing the blue-purple edge phenomenon of the imaging. Conditional equations 1) to 7) are as follows: 1) Nd 2 =1.59; Vd 2 =68.34; Nd 3 =1.78; Vd 3 =25.72; 2)Nd 4 =1.58; Vd 4 =40.89; Nd 5 =1.59; Vd 5 =68.34; 3) The refractive index temperature coefficient of the material of the second lens and the fifth lens is dn / dT<-6*10E-6 in the temperature range of -40°C to 105°C; 4) Vd 2 -Vd 3 =42.62; 5) Vd 5 -Vd 4 =27.45; 6)|R 11 -R 10 ∣>5;7)Nd 7 =1.95;

[0126] Table 4 Example 4 Parameters

[0127]

[0128]

[0129] See also Fig.32The MTF diagram of the lens in Example 4 under visible light 435-650nm shows that the MTF value is greater than 0.3 at 160lp / mm when the field of view angle FOV = 30.82° and the target surface size IMH = 8.86mm, indicating that this example has high resolution and good imaging quality. Fig.33 The MTF diagram of the lens in Example 4 at night at 850nm shows that the MTF value at 160lp / mm is greater than 0.28 when the field of view angle FOV = 30.82° and the target surface size IMH = 8.86mm, indicating that this example has high resolution and good imaging quality at night (850nm). Fig.34 , Example 4 lens TFM diagram under visible light 435-650nm, field of view angle FOV = 30.82°, target surface size IMH = 8.86mmMTF frequency at 73lp / mm focal depth> 35um, indicating that this example lens has good aberration and large focal depth. Please refer to Fig.35 , Example 4 lens TFM diagram at night at 850nm, field of view angle FOV = 30.82°, target surface size IMH = 8.86mmMTF frequency is 73lp / mm, the lower lens visible and infrared center field of view defocus <6um. Please refer to Fig.36 , Example 4 lens field curvature and distortion diagram, the field curvature curve at 435-650 wavelengths in this example shows that both the T line and the S line have good convergence, the field curvature and astigmatism are both excellent, ensuring the uniform imaging of the entire image, the distortion < 2% in the absolute value symbol, the lens is close to a distortion-free lens. Please refer to Fig.37 , Light fan diagram of the lens in Example 4. This example has good correction for magnification chromatic aberration and coma at wavelengths of 435-650, meeting the pixel requirements. Fig.38 , the vertical axis chromatic aberration diagram of the lens in Example 4 shows that the magnification chromatic aberration and coma at wavelengths of 435-650 are well corrected, meeting the pixel requirements. Fig.39 , Example 4 lens relative illumination diagram under visible light 435nm-650nm, it can be seen that the relative illumination of the lens is greater than 60% when the target surface size IMH=8.86mm. Please refer to Fig.40 , Example 4 The maximum principal ray incident angle of the lens changes with the normalized image plane. It can be seen that the maximum principal ray incident angle of the lens is 13.5° when the target surface size IMH=8.86mm.

[0130] Based on Examples 1 to 4, this case has the following specific advantages:

[0131] 1. The high-throughput medium-long focal length lens of the present invention solves the problem of poor parfocality between day and night at the medium-long focal length end. In the design and development stage, it matches the 1 / 1.8-inch imaging target surface and can reach 8 million pixels. The full field resolution can reach 200lp / mm>0.3.

[0132] 2. The wide-light medium-long focal length lens of the present invention has a wavelength range of 435-650nm (visible light) and 850nm (night use), and a confocal design, so it can be used day and night without focusing.

[0133] 3. The high-through-light medium-long focal length lens of the present invention uses only 7 optical lenses, and the total optical length is controlled within 22 mm. The lens interface can meet the M12 thread. The internal ultra-compact optical structure is adopted. The overall design takes into account both volume and weight, meeting the requirements of lightweight design.

[0134] 4. The wide aperture medium and long focal length lens of the present invention has a wide aperture of F#2. Under the condition of wide aperture, it can take into account both 435nm wavelength and 850nm wavelength, and realize the design of 850nm confocal while reducing the undesirable phenomenon of blue-purple fringing. Even in a dark environment, due to the large aperture of F#2, it can still capture enough light to ensure that the monitoring light surface is clearly visible.

[0135] 5. Due to the characteristics of large light transmission and medium telephoto, it can provide better depth of field control when shooting, and can produce a blur effect in the background, thereby highlighting the monitoring target.

[0136] 6. The focal length of the high-throughput medium-long focal length lens of the present invention is 16mm, which is suitable for long-distance monitoring. While ensuring a wide viewing angle, it still has a certain telephoto capability and can capture clear images at a relatively long distance, which is an important advantage for long-distance monitoring scenarios.

[0137] 7. The large-light-through medium-long focal length lens of the present invention has small ghost image energy, small pixels occupied by ghost images, and small target surface area.

[0138] 8. The wide-light medium-to-long focal length lens of the present invention can effectively balance the low-order aberrations of the lens by reasonably controlling the materials used and the positive and negative distribution of the optical power of each lens, and at the same time reduce the sensitivity of the lens tolerance, thereby improving the resolving power of the optical system under the conditions that can be achieved in existing manufacturing, and increasing the resolution performance of the optical system.

[0139] Example 5

[0140] Reference Fig.41 , a description will be given of electronic device A according to Example 5 of the present invention. Fig.41 Schematic diagram of an electronic device (industrial camera) using any one of the high-light medium-long focal length day-night confocal lenses according to Examples 1 to 4 for an imaging optical system. Fig.41, reference numeral A2 denotes an electronic device body, and reference numeral A1 denotes an imaging optical system (interchangeable lens) including any one of the high-clearance medium-long focal length day / night confocal lenses according to Examples 1 to 4. Reference numeral A3 denotes an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor, which is built into the camera body A2 and receives light (optical image formed by the imaging optical system A1) from the imaging optical system A1 and performs photoelectric conversion.

[0141] By using the high-clearance medium-long focal length day / night confocal lens according to any one of Examples 1 to 4 for electronic devices such as digital still cameras, electronic devices having a high-clearance medium-long focal length day / night confocal lens with high optical performance can be obtained. Each example can provide an electronic device with high optical performance.

[0142] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A day and night confocal lens with large light transmission and medium-long focal length, characterized in that: From the object side to the image side, there are the first lens, the second lens, the aperture, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and at least one cemented lens group; wherein, The first lens has positive focal power, and has an object side surface facing the object side and an image side surface facing the object side, the object side surface is convex, and the image side surface is concave; the ratio range of the first lens to the focal length of the lens is: 0.961 to 1.280:1; The second lens has positive power, an object side surface facing the object side and an image side surface facing the object side, the object side surface is convex, and the image side surface is concave; the ratio of the second lens to the focal length of the lens is in the range of 0.719 to 1.514:1; The third lens has a negative refractive power, and has an object side surface facing the image side and an image side surface facing the object side, the object side surface is a convex surface, and the image side surface is a concave surface; the ratio range of the third lens to the focal length of the lens is: -0.716 to -0.348:1; The fourth lens has negative optical power, has an object side surface facing the object side and an image side surface facing the image side, the object side surface is a concave surface, and the image side surface is a concave surface; the ratio range of the fourth lens to the focal length of the lens is: -0.250 to -0.307:1; The fifth lens has positive power, has an object side surface facing the object side and an object side surface facing the object side, the object side surface is a convex surface, and the image side surface is a convex surface; the ratio of the fifth lens to the focal length of the lens is in the range of 0.250 to 0.328:1; The sixth lens has negative optical power, has an object side surface facing the object side and an image side surface facing the image side, the object side surface is a convex surface, and the image side surface is a convex surface; the ratio range of the sixth lens to the focal length of the lens is: -1.427 to -0.718:1; The seventh lens has positive focal power, an object side surface facing the object side and an image side surface facing the object side, the object side surface is convex, and the image side surface is convex; the ratio range of the seventh lens to the focal length of the lens is: 0.587-0.644:

1.

2. The high-clearance medium-long focal length day and night confocal lens according to claim 1, characterized in that: The first lens is a meniscus positive lens made of a high refractive index material; The sixth lens is a meniscus negative lens.

3. The high-clearance medium-long focal length day and night confocal lens as claimed in claim 1, characterized in that: The lens satisfies the following conditional formula: Nd2<1.6; Vd2>68 Nd3>1.7; Vd3<30 Wherein, Nd2 is the refractive index of the second lens; Vd2 is the Abbe coefficient of the second lens; Nd3 is the refractive index of the third lens; Vd3 is the Abbe coefficient of the third lens.

4. The high-clearance medium-long focal length day and night confocal lens as claimed in claim 1, characterized in that: The lens satisfies the following conditional formula: 1.55 <Nd4<1.65;Vd4<41 1.55 <Nd5<1.65;Vd5<69 Wherein, Nd4 is the refractive index of the fourth lens; Vd4 is the Abbe coefficient of the fourth lens; Nd5 is the refractive index of the fifth lens; Vd5 is the Abbe coefficient of the fifth lens.

5. The high-clearance medium-long focal length day and night confocal lens as claimed in claim 1, characterized in that: The refractive index temperature coefficient dn / dT of the material of the second lens and the fifth lens is less than -6*10E-6 in the temperature range of -40°C to 105°C.

6. The high-clearance medium-long focal length day and night confocal lens as claimed in claim 1, characterized in that: The second lens and the third lens are glued together to form a first glued lens group; The fourth lens and the fifth lens are cemented together to form a second cemented lens group; The aperture is arranged between the first cemented lens group and the second cemented lens group.

7. The high-clearance medium-long focal length day and night confocal lens as claimed in claim 1, characterized in that: The second lens and the third lens are glued together to form a first glued lens group; The lens satisfies the following conditional formula: Vd2-Vd3>33 Wherein, Vd2 is the Abbe coefficient of the second lens, and Vd3 is the Abbe coefficient of the third lens.

8. The high-clearance medium-long focal length day and night confocal lens as claimed in claim 1, characterized in that: The fourth lens and the fifth lens are cemented together to form a second cemented lens group; The lens satisfies the following conditional formula: Vd5-Vd4>27 Wherein, Vd4 is the Abbe coefficient of the fourth lens, and Vd5 is the Abbe coefficient of the fifth lens.

9. The high-clearance medium-long focal length day and night confocal lens as claimed in claim 1, characterized in that: The lens satisfies the following conditional formula: ∣R 11 -R 10 ∣>5;Nd7>1.85 In the formula, R 10 is the radius of curvature of the sixth lens on the object side, R 11 is the radius of curvature of the sixth lens on the image side; Nd7 is the refractive index of the seventh lens.

10. An electronic device, characterized in that: A day and night confocal lens with a large clear light and a medium-long focal length according to any one of claims 1 to 9; and The image sensor is configured to receive the image formed by the large-clearance medium-long focal length day and night confocal lens.

Images