A high-throughput medium-long focal length day-night confocal lens and electronic device

Abstract

This invention discloses a large-aperture medium-long focal length day-night confocal lens and electronic device. The lens comprises, from object side to image side, a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens has positive optical 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 of the first lens to the lens focal length ranges from 0.961 to 1.280:1. The second lens also has positive optical 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 of the second lens to the lens focal length ranges from 0.719 to 1.514:1, etc. This invention solves the confocal difference problem of medium-long focal length lenses during day and night use through lens configuration and reasonable optical power distribution.

Description

Technical Field

[0001] This invention relates to the field of medium-long focal length day and night confocal lens technology, and in particular to a large-aperture medium-long focal length day and night confocal lens and electronic device. Background Technology

[0002] Medium to long focal length lenses are widely used in security monitoring, improving both monitoring efficiency and the reliability and security of monitoring systems. However, existing medium to long focal length lenses have at least one of the following drawbacks:

[0003] 1) Generally, medium to long focal length lenses only cover the visible light wavelength range, which cannot meet the needs of nighttime use.

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

[0005] 3) Generally, medium to long focal length lenses have a small light transmission ratio. In low-light conditions, the light entering the lens is relatively low, resulting in a darker image.

[0006] 4) Generally, medium and long focal length lenses do not control distortion well, which can easily cause distortion of the image and the object, resulting in inaccurate recognition.

[0007] 5) Generally, medium to long focal length lenses exhibit noticeable blue fringing in visible light and poor color reproduction. Summary of the Invention

[0008] In view of this, the object of the present invention is to provide a large-aperture medium-long focal length day-night confocal lens and electronic device. This lens can at least solve one of the technical shortcomings mentioned in the background art.

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

[0010] In the above technical solution, the confocal difference problem of medium-long telephoto lenses during day and night use is solved by setting the lens and reasonably distributing the optical power. During the design phase, this invention achieved a high resolution of eight megapixels for a 1 / 1.8-inch imaging sensor, maintaining an excellent resolution of 200 lp / mm@0.3 across the entire field of view. The medium-long telephoto lens of this invention covers the visible light wavelength range of 435-650nm and the night vision wavelength of 850nm, employing a confocal design that allows for day and night use without adjusting the focal length. Furthermore, the lens consists of only seven optical elements, with a total optical length controlled within 22mm, compatible with M12 threaded interfaces, and features an extremely compact internal optical structure. The overall design meets the requirements of lightweight design while ensuring size and weight. A ratio that satisfies the above relationship results in a smoother light angle, reducing tolerance sensitivity and improving the yield stability of the optical lens. The more even distribution of optical power among the individual elements also facilitates the miniaturization of the optical lens. The lens of this invention boasts a large F2 aperture, enabling it to capture sufficient light even in low-light environments, ensuring the clarity of the monitored image. Thanks to the large aperture, the lens provides excellent depth-of-field control during shooting, producing a good bokeh effect in the background to highlight the monitored target. With a focal length of 16.3mm, it is suitable for long-distance monitoring, ensuring both a wide field of view and a certain telephoto capability, enabling the capture of clear images at considerable distances, which is crucial for long-distance monitoring scenarios. Furthermore, the lens of this invention exhibits excellent ghosting control, with low ghosting energy and a small pixel and target area footprint. By rationally selecting lens materials and precisely allocating positive and negative values ​​of optical power, this invention effectively balances the lens's low-order aberrations and reduces sensitivity to manufacturing tolerances, improving the resolution and overall performance of the optical system, achieving superior optical performance even under current manufacturing conditions.

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

[0012] In the aforementioned technical solution, the first lens adopts a meniscus design, and the use of a high-refractive-index material 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 lens miniaturization but also supports distortion-free optical performance. The sixth lens is a concave negative lens, which can effectively diverge light, thereby increasing the image plane size and reducing the angle at which the principal ray enters the sensor. This design not only optimizes image 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] Nd2 < 1.6; Vd2 > 68

[0015] Nd3>1.7; Vd3<30

[0016] In the formula, 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; and Vd3 is the Abbe coefficient of the third lens.

[0017] In the above technical solution, the combination of high and low dispersion materials is beneficial for correcting second-order chromatic aberration, effectively improving image quality. Axial chromatic aberration can be corrected by two lenses, the second and third lenses. The positive focal length second lens has lower dispersion, i.e., a higher Abbe number, while the negative focal length third lens has higher dispersion, i.e., a lower Abbe number. This lens group can correct primary chromatic aberration, ensuring that the focal points of the cutoff long-wavelength red light and the short-wavelength blue light coincide on the optical axis. This effective correction of chromatic aberration results in advantages such as minimal blue-violet fringing and clear optical imaging performance.

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

[0019] 1.55 <Nd4<1.65;Vd4<41

[0020] 1.55 <Nd5<1.65;Vd5<69

[0021] In the formula, 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; and Vd5 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 a positive focal length, has lower dispersion, i.e., a higher Abbe number, while the fourth lens, with a negative focal length, has higher dispersion, i.e., a lower Abbe number. This lens group can correct primary chromatic aberration, ensuring that the focal points of the cutoff long-wavelength red light and the short-wavelength blue light coincide on the optical axis. This effective correction of chromatic aberration results in advantages such as minimal blue-violet fringing and clear optical imaging performance.

[0023] In some embodiments, the refractive index temperature coefficients dn / dT of the materials of the second lens and the fifth lens are less than -6*10E-6 in the temperature range of -40℃ to 105℃.

[0024] In the above technical solution, the use of materials with a special refractive index temperature coefficient can effectively balance temperature drift and achieve heatless imaging. The second and fifth lenses with positive focal lengths are made of materials with negative refractive index temperature coefficients, which can effectively reduce the image plane shift caused by thermal expansion and contraction of lens components. This allows the lens to operate without additional focusing at different temperatures, increasing the consistency of image clarity across different temperatures, thus balancing temperature drift and achieving the goal of heatless imaging.

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

[0026] In the above technical solution, the second lens, a meniscus positive lens, and the third lens, a meniscus negative lens, together constitute a first cemented lens group on the object side with negative optical power. This combination works synergistically with the first lens to handle the imaging range of the wide-angle field of view, effectively compensating for the aberrations generated by the first lens at large field of view angles. Furthermore, this combination reduces the impact on the sensing element by suppressing the incident angle of off-axis field-of-view rays, resulting in smaller incident angles of light rays from the edge field of view onto subsequent optical elements, thereby further correcting off-axis field-of-view aberrations and improving the resolution of the optical system. The fourth lens, a biconcave negative lens, and the fifth lens, a biconvex positive lens, form a second cemented lens group on the object side with positive optical power. This combination, through the design of the cemented lenses, effectively converges the angle at which light enters the aperture stop and rear group, reducing the angle sensitivity of the large-aperture, wide-angle optical lens. Simultaneously, this combination plays a crucial role in correcting spherical aberration and coma at large field of view, further balancing the aberrations generated by the front lens elements. The second and fifth lenses, with positive focal lengths, have lower chromatic aberration (i.e., higher Abbe numbers), while the third and fourth lenses, with negative focal lengths, have higher chromatic aberration (i.e., lower Abbe numbers). This combination of the first cemented lens group C1 and the second cemented lens group C2 corrects primary chromatic aberration, ensuring that the long-wavelength red light and short-wavelength blue light converge on the optical axis. In the optical system layout, an aperture stop is placed between the first and second cemented lens groups, forming a double-Gaussian lens structure. In this structure, the positive distortion characteristics of the front group are fully utilized to overcome the traditional limitations of double-Gaussian lenses, such as low light transmission and significant distortion. This design not only optimizes the efficiency of light entering the aperture stop 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 condition:

[0028] Vd2-Vd3>33

[0029] In the formula, Vd2 is the Abbe coefficient of the second lens, and Vd3 is the Abbe coefficient of the third lens.

[0030] In the above technical solution, the second lens, a meniscus positive lens, and the third lens, a meniscus negative lens, together constitute a first cemented lens group on the object side with negative optical power. This group works synergistically with the first lens to handle the imaging range of the wide-angle field of view, effectively compensating for the aberrations generated by the first lens at large field of view angles. Furthermore, this group reduces the impact on the sensing element by suppressing the incident angle of off-axis field-of-view rays, resulting in smaller incident angles of rays from the edge field of view on subsequent optical elements, thereby further correcting off-axis field-of-view aberrations and improving the resolution of the optical system. Simultaneously, the combination of high- and low-dispersion materials is beneficial for correcting second-order chromatic aberration, effectively improving image quality.

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

[0032] Vd5-Vd4>27

[0033] In the formula, Vd4 is the Abbe coefficient of the fourth lens, and Vd5 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 optical power. This combination, through the design of the cemented lens, effectively converges the angle at which light enters the aperture and the rear group, reducing the angular sensitivity of the large-aperture, wide-angle optical lens. Simultaneously, this combination plays a crucial role in correcting spherical aberration and coma in a large field of view, further balancing the aberrations generated by the front lens elements. The combination of high and low dispersion materials is beneficial for correcting second-order chromatic aberration, effectively improving image quality. The fourth, fifth, and sixth lenses form the second lens group, which is a cemented triplet lens. Its advantage is the elimination of chromatic aberration. By using the curvature radius, thickness, and different optical materials of the three different elements, chromatic aberration is eliminated, ensuring that the long-wavelength red light and the short-wavelength blue light converge on the optical axis, reducing the blue-violet fringing phenomenon in the image.

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

[0036] |R 11 -R 10 ∣>5

[0037] Nd7>1.85

[0038] Where R 10 R is the radius of curvature value on the side of the sixth lens. 11Nd7 is the radius of curvature on the image side of the sixth lens; Nd7 is the refractive index of the seventh lens.

[0039] In the aforementioned technical solutions, the performance of lenses is influenced by various factors in the field of optical design. For concentric circle lenses, the yield rate of their optical properties during the cold-working and grinding stage is low, and the eccentricity accuracy is difficult to guarantee. This is mainly due to the influence of the lens's geometry and manufacturing tolerances. To overcome these limitations, this invention sets |R... 11 -R 10 5. The seventh lens is designed using a high-refractive-index material. This strategy not only optimizes the lens's optical performance and improves image resolution but also effectively reduces the lens's rear outer diameter. This design allows the lens to meet the specifications of the M12 threaded mount, thus enhancing its versatility in various imaging systems. The use of high-refractive-index materials enables a more compact design while maintaining high optical performance, which is significant for improving system integration and portability. Furthermore, the compatibility of the M12 threaded mount allows the lens to easily adapt to various standard cameras and imaging devices, thereby broadening its applicability in different optical systems.

[0040] According to another aspect of the present invention, an electronic device is provided, comprising a large-aperture medium-long focal length day-night confocal lens as described above; and an image sensor configured to receive an image formed by the large-aperture medium-long focal length day-night confocal lens.

[0041] In the above technical solution, the advantage of this electronic device relies on a large-aperture medium-long focal length day and night confocal lens, which will not be elaborated here. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

[0044] Figure 2 This is the MTF diagram of a large-aperture 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 at 850nm at night for Example 1 of a large-aperture medium-long focal length day-night confocal lens of the present invention;

[0046] Figure 4 This is a TFM image of a large-aperture medium-long focal length day-night confocal lens of the present invention at visible light 435-650nm.

[0047] Figure 5 This is a TFM image of a large-aperture medium-long focal length day-night confocal lens of the present invention at visible light 435-650nm.

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

[0049] Figure 7 This is an example 1 of the present invention: a large-aperture medium-long focal length day-night confocal lens;

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

[0051] Figure 9 This is a relative illumination diagram of a large-aperture medium-long focal length day-night confocal lens of the present invention at visible light 435nm-650nm.

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

[0053] Figure 11 This is a schematic diagram of the structure of Example 2 of a large-aperture medium-long focal length day and night confocal lens of the present invention;

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

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

[0056] Figure 14 This is a TFM image of a large-aperture medium-long focal length day-night confocal lens example 2 of the present invention in the visible light 435-650nm range;

[0057] Figure 15 This is a TFM image of a large-aperture medium-long focal length day-night confocal lens example 2 of the present invention in the visible light 435-650nm range;

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

[0059] Figure 17 This is an example 2 of the optical fan diagram of a large-aperture medium-long focal length day and night confocal lens of the present invention;

[0060] Figure 18 This is a chromatic aberration diagram of Example 2 of a large-aperture medium-long focal length day-night confocal lens of the present invention;

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

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

[0063] Figure 21 This is a schematic diagram of the structure of Example 3 of a large-aperture medium-long focal length day and night confocal lens of the present invention;

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

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

[0066] Figure 24 This is a TFM image of a large-aperture medium-long focal length day-night confocal lens of the present invention at visible light 435-650nm.

[0067] Figure 25 This is a TFM image of a large-aperture medium-long focal length day-night confocal lens of the present invention at visible light 435-650nm.

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

[0069] Figure 27 This is an example 3 of the optical fan diagram of a large-aperture medium-long focal length day and night confocal lens of the present invention;

[0070] Figure 28 This is a chromatic aberration diagram of Example 3 of a large-aperture medium-long focal length day-night confocal lens of the present invention;

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

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

[0073] Figure 31 This is a schematic diagram of the structure of Example 4 of a large-aperture medium-long focal length day-night confocal lens of the present invention;

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

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

[0076] Figure 34 This is a TFM image of a large-aperture medium-long focal length day-night confocal lens of the present invention at visible light 435-650nm.

[0077] Figure 35 This is a TFM image of a large-aperture medium-long focal length day-night confocal lens of the present invention at visible light 435-650nm.

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

[0079] Figure 37 This is the fan-shaped diagram of Example 4 of a large-aperture medium-long focal length day-night confocal lens of the present invention;

[0080] Figure 38 This is a chromatic aberration diagram of Example 4 of a large-aperture medium-long focal length day-night confocal lens of the present invention;

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

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

[0083] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0084] The purpose of this invention is to provide a high-performance, large-aperture, medium-long focal length day-night confocal lens and electronic device. Embodiments according to the invention will now be described in detail with reference to the accompanying drawings. Figure 1 , Figure 11 , Figure 21 , Figure 31 These are cross-sectional views of large-aperture medium-long focal length day-night confocal lenses (optical systems) according to Examples 1 to 4. The large-aperture medium-long focal length day-night confocal lenses according to each example are used in imaging equipment including digital video cameras, digital still cameras, broadcast cameras, surveillance cameras, etc., and in electronic devices with 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 the aperture stop (fixed aperture stop or visible aperture stop), OA represents the optical axis, G1 is the filter, and G2 is the protective film. IMA represents the image plane, and when the large-aperture medium-long focal length day-night confocal lenses 1 to 4 according to each example are used in the imaging optical system of a digital video camera or 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 image plane IMA.

[0085] According to various examples, the large-aperture telephoto day / night confocal lenses, arranged in order from the object side to the image side, include: 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 optical power, has an object-side surface facing the object side and an image-side surface facing the object side, the object-side surface being convex and the image-side surface being concave; the ratio of the first lens to the lens focal length is in the range of 0. The second lens L2 has positive optical 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 of the second lens to the focal length of the lens ranges from 0.719 to 1.514:1. The third lens L3 has negative optical 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 convex, and the image-side surface is concave. The ratio of the third lens to the focal length of the lens ranges from 0.961 to 1.280:1.

[0086] -0.716 to -0.348:1; The fourth lens L4 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 concave, and the image-side surface is concave; the ratio of the fourth lens to the lens focal length ranges from -0.250 to -0.307:1; The fifth lens L5 has 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 convex, and the image-side surface is convex; the ratio of the fifth lens to the lens focal length ranges from 0.250 to 0.328:1; The sixth lens L6 has negative optical power, has an object-side surface facing the object side and an image-side surface facing the image side. The image-side surface facing the image side is convex, and the object-side surface is convex. The ratio of the focal length of the sixth lens to the focal length of the lens ranges from -1.427 to -0.718:1. The seventh lens L7 has positive optical 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 convex. The ratio of the focal length of the seventh lens to the focal length of the lens ranges from 0.587 to 0.644:1. When the ratio satisfies the above relationship, the light rays will have a gentler angle, reducing tolerance sensitivity and improving the yield stability of the optical lens. The more even distribution of optical power among the lenses 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 concave negative lens; and the seventh lens is a plano-convex positive lens.

[0088] According to the examples of large-aperture telephoto lenses for day and night confocal lenses, at least one of the following setting conditions 1) to 7) can be satisfied:

[0089] 1)Nd2<1.6; Vd2>68; Nd3>1.7; Vd3<30;

[0090] 2) 1.55 <Nd4<1.65;Vd4<41;1.55<Nd5<1.65;Vd5<69;

[0091] 3) The refractive index temperature coefficients dn / dT of the materials of the second lens and the fifth lens are less than -6*10E-6 in the temperature range of -40℃ to 105℃.

[0092] 4) Vd2 - Vd3 > 33;

[0093] 5) Vd5 - Vd4 > 27;

[0094] 6) |R 11 -R 10 |>5;

[0095] 7) Nd7 > 1.85;

[0096] In the above conditional expressions, 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; 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; R 10 R is the radius of curvature value on the side of the sixth lens. 11 Nd7 is the radius of curvature on the image side of the sixth lens; Nd7 is the refractive index of the seventh lens.

[0097] Condition 1) defines the refractive index and Abbe number of the second and third lenses. By appropriately setting the conditions, the two lenses are made of high- and low-dispersion materials, which is beneficial for correcting second-order chromatic aberration and can effectively improve image quality. Specifically: if the refractive index of the second lens is higher than the upper limit, it will be 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 detrimental to correcting 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 detrimental to correcting axial chromatic aberration and magnification chromatic aberration of the lens. Furthermore, to reliably obtain the effect of condition 1), it is more preferable to set the value of condition 1) to Nd2 = 1.59.

[0098] Vd2=38.34; Nd3=1.72.; Vd3=28.32

[0099] Condition 2) defines the refractive index and Abbe number of the fourth and fifth lenses. By appropriately setting the conditions, an achromatic effect (the focal points of the cutoff long-wavelength red light and the short-wavelength blue light coincide on the optical axis) is achieved. Among these settings: if the refractive index of the fourth lens is below the lower limit or above the upper limit, it will lead to uneven optical power distribution and reduced tolerance, resulting in low yield. If the refractive index of the fifth lens is below the lower limit or above the upper limit, it will lead to poor temperature drift. If the Abbe number of the fourth lens is above the upper limit, it will result in weak optical aberration compensation and balance before the aperture stop, preventing light from entering the image plane at a gentle angle. If the Abbe number of the fifth lens is above the upper limit, it will lead to poor correction of axial chromatic aberration and magnification chromatic aberration of the lens. Furthermore, to reliably obtain the effect of condition 2), it is preferable to set the values ​​of condition 2) to Nd4 = 1.60; Vd4 = 38; Nd5 < 1.65; Vd5 = 68.34.

[0100] Condition 3) defines the temperature coefficients of the second and fifth lenses. By appropriately setting the conditions and using materials with special refractive index temperature coefficients, temperature drift can be effectively balanced, achieving calorific value. Furthermore, to reliably obtain the effect of condition 2), the material selection can include H-ZPK5, H-ZPK7, FCD515, and FCD1.

[0101] Condition 4) defines the difference in Abbe number between the second and third lenses in the first cemented lens group. By appropriately setting the conditions, the combination of high and low dispersion materials is beneficial for correcting second-order chromatic aberration and can effectively improve image quality. Specifically, if the value is lower than the lower limit, it will result in insufficient correction of axial chromatic aberration and magnification chromatic aberration of the lens. Furthermore, to reliably obtain the effect of condition 4), it is more preferable to set the value of condition 4) to Vd2-Vd3=40.

[0102] Condition 5) defines the difference in Abbe number between the fifth and fourth lenses in the second cemented lens group. By appropriately setting the conditions, the combination of high and low dispersion materials is beneficial for correcting second-order chromatic aberration and can effectively improve image quality. However, if the value is below the lower limit, it will result in insufficient correction of axial chromatic aberration and magnification chromatic aberration of the lens. Furthermore, to reliably obtain the effect of condition 5), it is more preferable to set the value of condition 5) to Vd5 - Vd4 = 30.

[0103] Condition 6) defines the radius of curvature values ​​of the front and rear surfaces of the sixth lens. By appropriately setting the conditions, the low yield and difficulty in ensuring eccentricity accuracy during the cold working and grinding stage of concentric circular lenses can be mitigated. Furthermore, to reliably obtain the effect of condition 6), it is more preferable to set the value of condition 6) to |R11-R10|.

[0104] =5.5、.

[0105] Condition 7) defines the refractive index of the seventh lens. By appropriately setting the conditions, the design of the seventh lens utilizes a material with a high refractive index. This strategy not only optimizes the optical performance of the lens and improves imaging resolution, but also effectively reduces the outer diameter of the lens's rear end. Furthermore, to reliably obtain the effect of condition 7), it is more preferable to set the value of condition 7) to 1.75, and even more preferable to set it to 1.90.

[0106] A detailed description of a large-aperture telephoto lens with day and night confocal focus, based on various examples, will now be provided.

[0107] Example 1

[0108] Please refer to the optical structure of Example 1. Figure 1The specific parameters of Example 1 are shown in Table 1 below. In Example 1, the lens F# = 2, the lens focal length f = 16.3mm, the diagonal field of view (FOV) = 30.80, the total length TTL = 22.00; the optical back focal length (BFL) = 8.20; the lens design image height h = 8.86; TTL / h = 2.48 (this parameter indicates that the present invention can achieve 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 present invention can achieve large angular resolution and achieve a wider field of view at different focal lengths). The second lens L2 and the third lens L3 are cemented together to form the first cemented lens group C1; the fourth lens L4 and the fifth lens L5 are cemented together to form the second cemented lens group C2; the aperture ST is disposed between the first cemented lens group C1 and the second cemented lens group C2. Conditions 1) to 7) are as follows: 1) 1Nd2 = 1.59; Vd2 = 68.34; Nd3 = 1.73; Vd3 = 28.32; 2) Nd4 = 1.61; Vd4 = 37; Nd5 = 1.59; Vd5 = 68.34; 3) The refractive index temperature coefficients dn / dT of the materials of the second lens and the fifth lens are < -6*10E-6 in the temperature range of -40℃ to 105℃; 4) Vd2 - Vd3 = 40.02; 5) Vd5 - Vd4 = 31.34; 6) |R 11 -R 10 |>5;7)Nd7=1.91;

[0109] Table 1 Example 1 Parameter Table

[0110]

[0111]

[0112] Please see Figure 2 Example 1 shows the MTF (Mean Transformation Factor) of the lens in the visible light range of 435-650nm. With a field of view (FOV) of 30.8° and a target size (IMH) of 8.86mm, the MTF value is greater than 0.4 at 160 lp / mm, indicating high resolution and good image quality in this example. Please refer to... Figure 3 Example 1 shows the MTF (Mean Transformation Factor) of the lens at 850nm in low light. With a field of view (FOV) of 30.8° and a target size (IMH) of 8.86mm, the MTF value is greater than 0.2 at 160 lp / mm, indicating that this example demonstrates high resolution and good image quality at 850nm in low light. Please refer to... Figure 4 Example 1 shows the TFM pattern of the lens in the visible light range of 435-650nm. With a field of view (FOV) of 30.8°, a target size (IMH) of 8.86mm, and an MTF frequency of 73 lp / mm, the depth of focus is >40µm, indicating that this example lens has good aberrations and a large depth of focus. Please refer to... Figure 5Example 1 shows the TFM image of the lens at 850nm in nighttime. With a field of view (FOV) of 30.82°, a target size (IMH) of 8.86mm, and an MTF frequency of 73 lp / mm, the defocusing amount between the visible and infrared center fields of view is <7µm. Please refer to [link / reference]. Figure 6 Example 1 shows the field curvature and distortion diagrams of the lens. According to the image, the field curvature curves in this example at wavelengths of 435-650 nm show excellent convergence of the T-line and S-line. Both field curvature and astigmatism are excellent, ensuring uniform imaging across the entire image. Distortion is less than 2% in absolute value, making the lens nearly distortion-free. (For further information, please refer to the lens documentation.) Figure 7 Example 1 shows the lens's aperture pattern, which demonstrates excellent correction for chromatic aberration and coma at wavelengths of 435-650 nm, meeting pixel requirements. Please refer to [link / reference]. Figure 8 Example 1 shows the transverse chromatic aberration diagram of the lens, which demonstrates excellent correction for magnification chromatic aberration and coma across wavelengths of 435-650 nm, meeting pixel requirements. Please refer to... Figure 9 Example 1 shows the relative illuminance diagram of the lens in the visible light range of 435nm-650nm. It can be seen that the lens achieves a relative illuminance greater than 60% while maintaining a target surface size of IMH = 8.86mm. Please refer to [link / reference]. Figure 10 Example 1 shows the variation of the maximum principal ray incident angle of the lens 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 plane size is IMH = 8.86mm.

[0113] Example 2

[0114] Please refer to the optical structure of Example 2. Figure 11The specific parameters of Example 2 are shown in Table 2 below. In Example 2, the lens F# = 2, the lens focal length f = 16.3mm, the diagonal field of view (FOV) = 30.80, and the total length TTL = 22.00; the optical back focal length (BFL) = 7.7; the lens design image height h = 8.86; TTL / h = 2.48 (this parameter indicates that the present invention can achieve miniaturization of the optical lens, with a shorter total length under the same imaging range); (FOV*f) / h = 56.66 (this parameter indicates that the present invention can achieve a large angular resolution, achieving a wider field of view at different focal lengths). Furthermore, the second and third lenses do not employ a cemented lens design. The fourth lens L4 and the fifth lens L5 are cemented together to form the first cemented lens group C1; the aperture ST is positioned between the third lens L3 and the second cemented lens group C1. Conditions 1) to 7) are as follows: 1) Nd2 = 1.59; Vd2 = 68.34; Nd3 = 1.72; Vd3 = 34.76; 2) Nd4 = 1.58; Vd4 = 40.75; Nd5 = 1.59; Vd5 = 68.34; 3) The refractive index temperature coefficient dn / dT of the materials of the second lens and the fifth lens in the temperature range of -40℃ to 105℃ is < -6*10E-6; 4) Vd2 - Vd3 = 33.58; 5) Vd5 - Vd4 = 27.59; 6) |R 11 -R 10 |>5;7)Nd7=1.95;

[0115] Table 2 Example 2 Parameter Table

[0116]

[0117]

[0118] Please see Figure 12 Example 2 shows the MTF (Mean Transformation Factor) of the lens in the visible light range of 435-650nm. With a field of view (FOV) of 30.82° and a target size (IMH) of 8.86mm, the MTF value is greater than 0.3 at 160 lp / mm, indicating high resolution and good image quality in this example. Please refer to... Figure 13 Example 2 shows the MTF (Mean Transformation Factor) of the lens at 850nm in low light. With a field of view (FOV) of 30.82° and a target size (IMH) of 8.86mm, the MTF value is greater than 0.12 at 160 lp / mm, indicating that this example demonstrates high resolution and good image quality at 850nm in low light. Please refer to... Figure 14 Example 2 shows the TFM pattern of the lens in the visible light range of 435-650nm. With a field of view (FOV) of 30.82°, a target size (IMH) of 8.86mm, and an MTF frequency of 73 lp / mm, the depth of focus is >40µm, indicating that this example lens has good aberrations and a large depth of focus. Please refer to... Figure 15Example 2 shows the TFM image of the lens at 850nm in nighttime. With a field of view (FOV) of 30.82°, a target size (IMH) of 8.86mm, and an MTF frequency of 73 lp / mm, the defocusing amount between the visible and infrared center fields of view is <10µm. Please refer to [link / reference]. Figure 16 Example 2 shows the field curvature and distortion diagrams of the lens. The field curvature curves for wavelengths of 435-650 nm in this example show excellent convergence of the T-line and S-line, with excellent field curvature and astigmatism, ensuring uniform imaging across the entire image. Distortion is less than 2% in absolute value, making the lens nearly distortion-free. Please refer to... Figure 17 Example 2 shows the lens's aperture pattern. This embodiment demonstrates excellent correction for chromatic aberration and coma at wavelengths of 435-650 nm, meeting pixel requirements. Please refer to... Figure 18 Example 2 shows the transverse chromatic aberration diagram of the lens, which demonstrates excellent correction for magnification chromatic aberration and coma in the 435-650 nm wavelength range, meeting pixel requirements. Please refer to... Figure 19 Example 2 shows the relative illuminance diagram of the lens in the visible light range of 435nm-650nm. It can be seen that the lens achieves a relative illuminance greater than 60% while maintaining a target surface size of IMH = 8.86mm. Please refer to [link / reference]. Figure 20 Example 2 shows the variation of the maximum principal ray incident angle of the lens with the normalized image plane. It can be seen that the maximum principal ray incident angle of the lens is 13° when the target plane size is IMH = 8.86mm.

[0119] Example 3

[0120] Please refer to the optical structure of Example 3. Figure 21The specific parameters of Example 3 are shown in Table 3 below. In Example 3, the lens F# = 2, the lens focal length f = 16.3 mm, the diagonal field of view (FOV) = 30.56, the total length TTL = 22.00; the optical back focal length (BFL) = 7.24; the lens design image height h = 8.86; TTL / h = 2.48 (this parameter indicates that the present invention can achieve miniaturization of the optical lens, and the total length is shorter under the same imaging range); (FOV*f) / h = 56.21 (this parameter indicates that the present invention can achieve large angular resolution and achieve a wider field of view at different focal lengths). The second lens L2 and the third lens L3 are cemented together to form the first cemented lens group C1; the fourth lens L4 and the fifth lens L5 are cemented together to form the second cemented lens group C2; the aperture ST is disposed between the first cemented lens group C1 and the second cemented lens group C2. Conditions 1) to 7) are as follows: 1) Nd2 = 1.59; Vd2 = 68.34; Nd3 = 1.74; Vd3 = 27.77; 2) Nd4 = 1.62; Vd4 = 36.33; Nd5 = 1.59; Vd5 = 68.34; 3) The refractive index temperature coefficients dn / dT of the materials of the second lens and the fifth lens are < -6*10E-6 in the temperature range of -40℃ to 105℃; 4) Vd2 - Vd3 = 40.57; 5) Vd5 - Vd4 = 32.04; 6) |R 11 -R 10 |>5;7)Nd7=1.95;

[0121] Table 3 Example 3 Parameter Table

[0122]

[0123] Please see Figure 22 Example 3 shows the MTF (Mean Transformation Factor) of the lens in the visible light range of 435-650nm. With a field of view (FOV) of 30.82° and a target size (IMH) of 8.86mm, the MTF value is greater than 0.3 at 160 lp / mm, indicating high resolution and good image quality in this example. Please refer to [link / reference]. Figure 23 Example 3 shows the MTF (Mean Transformation Factor) of the lens at 850nm in low light. With a field of view (FOV) of 30.82° and a target size (IMH) of 8.86mm, the MTF value is greater than 0.2 at 160 lp / mm, indicating that this example demonstrates high resolution and good image quality at 850nm in low light. Please refer to... Figure 24 Example 3 shows the TFM pattern of the lens in the visible light range of 435-650nm. With a field of view (FOV) of 30.82°, a target size (IMH) of 8.86mm, and an MTF frequency of 73 lp / mm, the depth of focus is >35µm, indicating that this example lens has good aberrations and a large depth of focus. Please refer to... Figure 25Example 3 shows the TFM image of the lens at 850nm in nighttime. With a field of view (FOV) of 30.82°, a target size (IMH) of 8.86mm, and an MTF frequency of 73 lp / mm, the defocusing amount between the visible and infrared center fields of view is <6µm. Please refer to [link / reference]. Figure 26 Example 3 shows the field curvature and distortion diagrams of the lens. The field curvature curves in this example (35-650 nm wavelength) show excellent convergence of the T-line and S-line, with excellent field curvature and astigmatism, ensuring uniform imaging across the entire image. Distortion is less than 2% in absolute value, making the lens nearly distortion-free. Please refer to... Figure 27 Example 3 shows the lens's fan-shaped aperture. This example demonstrates excellent correction for chromatic aberration and coma at wavelengths of 435-650 nm, meeting pixel requirements. Please refer to... Figure 28 Example 3 shows the transverse chromatic aberration diagram of the lens, which demonstrates excellent correction for magnification chromatic aberration and coma in the 435-650 nm wavelength range, meeting pixel requirements. Please refer to... Figure 29 Example 3 shows the relative illuminance diagram of the lens in the visible light range of 435nm-650nm. It can be seen that the lens achieves a relative illuminance greater than 60% while maintaining a target surface size of IMH = 8.86mm. Please refer to [link / reference]. Figure 30 Example 3 shows the variation of the maximum principal ray incident angle of the lens with the normalized image plane. It can be seen that the maximum principal ray incident angle of the lens is 13° when the target plane size IMH = 8.86mm.

[0124] Example 4

[0125] Please refer to the optical structure of Example 4. Figure 31The specific parameters of Example 4 are shown in Table 4 below. In Example 4, the lens F# = 2, the lens focal length f = 16.3mm, the diagonal field of view (FOV) = 31.09, and the total length TTL = 22.00; the optical back focal length (BFL) = 8; the lens design image height h = 8.86; TTL / h = 2.48 (this parameter indicates that the present invention can achieve miniaturization of the optical lens, and the total length is shorter under the same imaging range); (FOV*f) / h = 57.19 (this parameter indicates that the present invention can achieve large angular resolution and achieve a wider field of view at different focal lengths). The second lens L2 and the third lens L3 are cemented together to form the first cemented lens group C1; the fourth lens L4, the fifth lens L5, and the sixth lens L6 are cemented together to form the second cemented lens group C2; the aperture ST is disposed between the first cemented lens group C1 and the second cemented lens group C2. The advantage of this setup is the elimination of chromatic aberration. Chromatic aberration is eliminated by using the curvature radius, thickness, and different optical materials of three different elements, ensuring that the focal points of the cutoff long-wavelength red light and the short-wavelength blue light coincide on the optical axis, thus reducing the blue-violet fringing phenomenon in the image. Conditions 1) to 7) are as follows: 1) Nd2 = 1.59; Vd2 = 68.34; Nd3 = 1.78; Vd3 = 25.72; 2) Nd4 = 1.58; Vd4 = 40.89; Nd5 = 1.59; Vd5 = 68.34; 3) The refractive index temperature coefficient dn / dT of the materials of the second lens and the fifth lens is < -6*10E-6 within the temperature range of -40℃ to 105℃; 4) Vd2 - Vd3 = 42.62; 5) Vd5 - Vd4 = 27.45; 6) |R 11 -R 10 |>5;7)Nd7=1.95;

[0126] Table 4 Example 4 Parameter Table

[0127]

[0128]

[0129] Please see Figure 32 Example 4 shows the MTF (Mean Transformation Factor) of the lens in the visible light range of 435-650nm. With a field of view (FOV) of 30.82° and a target size (IMH) of 8.86mm, the MTF value is greater than 0.3 at 160 lp / mm, indicating high resolution and good image quality in this example. Please refer to... Figure 33 Example 4 shows the MTF (Mean Transformation Factor) of the lens at 850nm in low light. With a field of view (FOV) of 30.82° and a target size (IMH) of 8.86mm, the MTF value is greater than 0.28 at 160 lp / mm, indicating that this example demonstrates high resolution and good image quality at 850nm in low light. Please refer to... Figure 34Example 4 shows the TFM pattern of the lens in the visible light range of 435-650nm. With a field of view (FOV) of 30.82°, a target size (IMH) of 8.86mm, and an MTF frequency of 73 lp / mm, the depth of focus is >35µm, indicating that this example lens has good aberrations and a large depth of focus. Please refer to... Figure 35 Example 4 shows the TFM image of the lens at 850nm in nighttime. With a field of view (FOV) of 30.82°, a target size (IMH) of 8.86mm, and an MTF frequency of 73 lp / mm, the defocusing amount between the visible and infrared center fields of view is <6µm. Please refer to [link / reference]. Figure 36 Example 4 shows the field curvature and distortion diagrams of the lens. The field curvature curves in the 35-650 nm wavelength range of Example 4 show excellent convergence of the T-line and S-line, with excellent field curvature and astigmatism, ensuring uniform imaging across the entire image. Distortion is less than 2% in absolute value, making the lens nearly distortion-free. Please refer to... Figure 37 Example 4 shows the lens's aperture fan diagram. This example demonstrates excellent correction for chromatic aberration and coma at wavelengths of 435-650 nm, meeting pixel requirements. Please refer to... Figure 38 Example 4 shows the transverse chromatic aberration diagram of the lens, which demonstrates excellent correction for magnification chromatic aberration and coma across wavelengths of 435-650 nm, meeting pixel requirements. Please refer to [link / reference]. Figure 39 Example 4 shows the relative illuminance diagram of the lens in the visible light range of 435nm-650nm. It can be seen that the lens achieves a relative illuminance greater than 60% while maintaining a target surface size of IMH = 8.86mm. Please refer to [link / reference]. Figure 40 Example 4 shows the variation of the maximum principal ray incident angle of the lens 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 plane size IMH = 8.86mm.

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

[0131] 1. The large-aperture medium-long focal length lens of this invention solves the problem of day-night confocal difference at the medium-long focal length. During the design and development phase, it is matched with a 1 / 1.8-inch imaging target surface, achieving eight megapixels. The full field-of-view resolution can reach 200 lp / mm > 0.3.

[0132] 2. The large-aperture medium-long focal length lens of the present invention has a wavelength range of 435-650nm (visible light) and 850nm (night use), and features a confocal design, allowing for day and night use without the need for focusing.

[0133] 3. The large-aperture medium-long focal length lens of the present invention uses only 7 optical lenses, with the total optical length controlled within 22mm. The lens interface can meet the M12 thread, and the internal structure adopts an ultra-compact optical structure. The overall design takes into account both size and weight, meeting the requirements of lightweight design.

[0134] 4. The large-aperture medium-long focal length lens of this invention achieves a large aperture of F2, accommodating both 435nm and 850nm wavelengths while reducing blue-violet fringing and featuring a confocal 850nm design. Even in low-light environments, the large F#2 aperture ensures sufficient light capture, guaranteeing clear visibility of the monitored surface.

[0135] 5. Due to its large aperture and long telephoto lens, it can provide good depth-of-field control during shooting, and can produce a blurring effect in the background, thereby highlighting the monitored target.

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

[0137] 7. The large-aperture medium-long focal length lens of the present invention has low ghost image energy, small ghost image pixel size, and small target area.

[0138] 8. The large-aperture medium-long focal length lens of the present invention can effectively balance the low-order aberrations of the lens by reasonably controlling the materials used in each lens and the positive and negative distribution of optical power, while reducing the sensitivity of lens tolerances. Under the conditions that can be achieved in existing manufacturing, it can improve the resolution of the optical system and increase the resolution performance of the optical system.

[0139] Example 5

[0140] For reference Figure 41 A description of an electronic device A according to Example 5 of the present invention will be given. Figure 41 This is a schematic diagram of an electronic device (industrial camera) used in a photographic optical system, based on any of the large-aperture, medium-telephoto, day-night confocal lenses from Examples 1 to 4. Figure 41 In the figures, reference numeral A2 indicates the main body of the electronic device, and reference numeral A1 indicates any of the camera optical systems (interchangeable lenses) including the large-aperture medium-long focal length day-night confocal lenses according to Examples 1 to 4. Reference numeral A3 indicates 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 (the optical image formed by the camera optical system A1) from the camera optical system A1 and performs photoelectric conversion.

[0141] By using a large-aperture medium-telephoto day-night confocal lens according to any one of Examples 1 to 4 in an electronic device such as a digital still camera, an electronic device with a large-aperture medium-telephoto day-night confocal lens and high optical performance can be obtained. The various examples can provide an electronic device with high optical performance.

[0142] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims will be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A large-aperture, medium-long focal length, day-night confocal lens, characterized in that, The lens consists of seven lenses, arranged sequentially from the object side to the image side as a first lens, a second lens, an aperture stop, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens; some of the first to seventh lenses form at least one cemented lens group; wherein... The first lens has positive optical 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 of the first lens to the focal length of the lens ranges from 0.961 to 1.280:

1. The second lens has positive optical 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 of the second lens to the focal length of the lens ranges from 0.719 to 1.514:

1. The third lens has 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 convex and the image-side surface is concave. The ratio of the third lens to the focal length of the lens ranges from -0.716 to -0.348:

1. The fourth lens has negative optical power, and 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 of the fourth lens to the focal length of the lens ranges from -0.250 to -0.307:

1. The fifth lens has positive optical power and has an object-side surface facing the object and an image-side surface facing the object. The object-side surface is convex, and the image-side surface is convex. The ratio of the fifth lens to the focal length of the lens ranges from 0.250 to 0.328:

1. The sixth lens has negative optical power, and 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 convex. The ratio of the sixth lens to the focal length of the lens ranges from -1.427 to -0.718:

1. The seventh lens has positive optical power and has an object-side surface facing the object and an image-side surface facing the object. The object-side surface is convex and the image-side surface is convex. The ratio of the seventh lens to the focal length of the lens ranges from 0.587 to 0.644:

1.

2. The large-aperture medium-long focal length day-night confocal lens as described in claim 1, characterized in that, The first lens is a meniscus positive lens made of a high refractive index material.

3. The large-aperture medium-long focal length day-night confocal lens as described in claim 1, characterized in that, The lens satisfies the following condition: Nd2 < 1.6; Vd2 > 68 Nd3>1.7; Vd3<30 In the formula, 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; and Vd3 is the Abbe coefficient of the third lens.

4. A large-aperture medium-long focal length day-night confocal lens as described in claim 1, characterized in that, The lens satisfies the following condition: 1.55 <Nd4<1.65;Vd4<41 1.55 <Nd5<1.65;Vd5<69 In the formula, 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; and Vd5 is the Abbe coefficient of the fifth lens.

5. A large-aperture medium-long focal length day-night confocal lens as described in claim 1, characterized in that, The refractive index temperature coefficients dn / dT of the materials of the second lens and the fifth lens are less than -6*10E-6 in the temperature range of -40℃ to 105℃.

6. A large-aperture medium-long focal length day-night confocal lens as described in claim 1, characterized in that, The second lens and the third lens are cemented together to form a first cemented lens group; The fourth lens and the fifth lens are cemented together to form a second cemented lens group; An aperture is positioned between the first cemented lens group and the second cemented lens group.

7. A large-aperture medium-long focal length day-night confocal lens as described in claim 1, characterized in that, The second lens and the third lens are cemented together to form a first cemented lens group; The lens satisfies the following condition: Vd2-Vd3>33 In the formula, Vd2 is the Abbe coefficient of the second lens, and Vd3 is the Abbe coefficient of the third lens.

8. A large-aperture medium-long focal length day-night confocal lens as described 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 condition: Vd5-Vd4>27 In the formula, Vd4 is the Abbe coefficient of the fourth lens, and Vd5 is the Abbe coefficient of the fifth lens.

9. A large-aperture medium-long focal length day-night confocal lens as described in claim 1, characterized in that, The lens satisfies the following condition: ∣R 11 -R 10 ∣>5mm;Nd7>1.85 Where R 10 R is the radius of curvature value on the side of the sixth lens. 11 Nd7 is the radius of curvature on the image side of the sixth lens; Nd7 is the refractive index of the seventh lens.

10. An electronic device, characterized in that, A high-throughput medium-long focal length day-night confocal lens according to any one of claims 1-9; and An image sensor is configured to receive images formed by the large-aperture, long-focal-length, day-night confocal lens.

Images